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1. Magnesium isotope fractionation processes during seafloor serpentinization and implications for serpentinite subduction

Author: S. G. Nielsen, F. Klein, H. R. Marschall, P. A. E. Pogge von Strandmann, and M. Auro
Subjects: Geology, QE1-996.5, Stratigraphy, QE640-699
Abstract: Studies of magnesium (Mg) isotope ratios in subduction zone lavas have revealed small but significant offsets from the mantle value with enrichments in the heavy isotopes. However, the very high concentration of Mg in the mantle contrasts with much lower concentrations in the subducted igneous crust and oceanic sediments, making these subduction components unlikely vehicles of the Mg isotope anomalies in arc lavas. Only serpentinites, which in various proportions form part of oceanic plates, have high Mg contents comparable to fresh mantle rocks, and they have thus been regarded as a potential source of exotic Mg in the source of arc magmas. In this study we analyzed serpentinite samples from different oceanic settings for their Mg isotopic compositions. The majority of samples are indistinguishable from the depleted mantle (δ26Mg=-0.24 ‰ ± 0.04 ‰) irrespective of their origin. Only a small number of seafloor-weathered serpentinites are slightly enriched in the heavy isotopes (up to δ26Mg=-0.14 ‰ ± 0.03 ‰), implying that bulk serpentinites are unlikely sources of isotopically anomalous Mg in subduction zones. We also developed a partial dissolution method in which 5 % acetic acid for 180 min was shown to fully dissolve the minerals brucite and iowaite while leaving the serpentine mineral chrysotile essentially undissolved. Partial dissolution of 11 bulk serpentinite samples revealed Mg isotopic composition of brucite (± iowaite) that is systematically ∼0.25 ‰ heavier than that of coexisting serpentine. Thus, preferential breakdown of brucite and/or iowaite in a subducted slab prior to serpentine could preferentially release isotopically heavy Mg, which could subsequently be transported into the source region of arc magmas. Such a scenario would require brucite/iowaite breakdown to occur at pressures in excess of 3 GPa and produce fluids with very high concentrations of Mg that could be transported to arc magma source regions. Whether these conditions are met in nature has yet to be experimentally investigated.
Published: 2024
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2. The role of atmospheric conditions in the Antarctic sea ice extent summer minima

Author: B. Mezzina, H. Goosse, F. Klein, A. Barthélemy, and F. Massonnet
Subjects: Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract: Understanding the variability of Antarctic sea ice is still a challenge. After decades of modest growth, an unprecedented minimum in the sea ice extent (SIE) was registered in summer 2017, and, following years of anomalously low SIE, a new record was established in early 2022. These two memorable minima have received great attention as single cases, but a comprehensive analysis of summer SIE minima is currently lacking. Indeed, other similar events are present in the observational record, although they are minor compared to the most recent ones, and a full analysis of all summer SIE minima is essential to separate potential common drivers from event-specific dynamics in order to ultimately improve our understanding of the Antarctic sea ice and climate variability. In this work, we examine sea ice and atmospheric conditions during and before all summer SIE minima over the satellite period up to 2022. We use observations and reanalysis data and compare our main findings with results from an ocean–sea ice model (NEMO–LIM) driven by prescribed atmospheric fields from ERA5. Examining SIE and sea ice concentration (SIC) anomalies, we find that the main contributors to the summer minima are the Ross and Weddell sectors. However, the two regions play different roles, and the variability of the Ross Sea explains most of the minima, with typical negative SIE anomalies about twice as large as the ones in the Weddell Sea. Furthermore, the distribution of SIC anomalies is also different: in the Weddell Sea, they exhibit a dipolar structure, with increased SIC next to the continent and decreased SIC at the sea ice margin, while the Ross Sea displays a more homogenous decrease. We also examine the role of wintertime sea ice conditions before the summer SIE minima and find mixed results depending on the period: the winter conditions are relevant in the most recent events, after 2017, but they are marginal for previous years. Next, we consider the influence of the atmosphere on the SIE minima, which is shown to play a major role: after analyzing the anomalous atmospheric circulation during the preceding spring, we find that different large-scale anomalies can lead to similar regional prevailing winds that drive the summer minima. Specifically, the SIE minima are generally associated with dominant northwesterly anomalous winds in the Weddell Sea, while a southwesterly anomalous flow prevails in the Ross Sea. Finally, we investigate the relative contribution of dynamic (e.g., ice transport) and thermodynamic (e.g., local melting) processes to the summer minima. Our results indicate that the exceptional sea ice loss in both the Ross and Weddell sectors is dominated at the large scale by thermodynamic processes, while dynamics are also present but with a minor role.
Published: 2024
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3. Transverse-spin-dependent azimuthal asymmetries of pion and kaon pairs produced in muon-proton and muon-deuteron semi-inclusive deep inelastic scattering

Author: G.D. Alexeev, M.G. Alexeev, C. Alice, A. Amoroso, V. Andrieux, V. Anosov, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badelek, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, M. Bodlak, F. Bradamante, C. Braun, A. Bressan, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, P.M.M. Correia, M.L. Crespo, D. D'Ago, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, F. Del Carro, I. Denisenko, O.Yu. Denisov, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, D. Ecker, A. Efremov, C. Elia, D. Eremeev, P. Faccioli, M. Faessler, M. Finger, M. Finger, jr., H. Fischer, K.J. Flöthner, W. Florian, J.M. Friedrich, V. Frolov, L.G. Garcia Ordòñez, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, D. Giordano, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, M. Grüner, A. Guskov, D. von Harrach, M. Hoffmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, A. Khatun, G.V. Khaustov, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Korzenev, A.M. Kotzinian, O.M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, K. Lavickova, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, A. Maltsev, S.A. Mamon, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, C. Menezes Pires, F. Metzger, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, D. Miura, Y. Miyachi, R. Molina, A. Moretti, A. Nagaytsev, D. Neyret, M. Niemiec, J. Nový, W.-D. Nowak, G. Nukazuka, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, H. Pekeler, J.-C. Peng, G. Pesaro, M. Pešek, D.V. Peshekhonov, M. Pešková, S. Platchkov, J. Pochodzalla, V.A. Polyakov, M. Quaresma, C. Quintans, G. Reicherz, C. Riedl, D.I. Ryabchikov, A. Rychter, A. Rymbekova, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, H. Schmieden, A. Selyunin, K. Sharko, L. Sinha, M. Slunecka, F. Sozzi, D. Spülbeck, A. Srnka, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, T. Triloki, V. Tskhay, B. Valinoti, B.M. Veit, J.F.C.A. Veloso, B. Ventura, M. Virius, M. Wagner, S. Wallner, K. Zaremba, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, and M. Ziembicki
Subjects: SIDIS, Di-hadron, Spin, Fragmentation, Transversity, Collins effect, Physics, QC1-999
Abstract: A set of measurements of azimuthal asymmetries in the production of pairs of identified hadrons in deep-inelastic scattering of muons on transversely polarised 6LiD (deuteron) and NH3 (proton) targets is presented. All available data collected in the years 2003–2004 and 2007/2010 with the COMPASS spectrometer using a muon beam of 160GeV/c at the CERN SPS were analysed. The asymmetries provide access to the transversity distribution functions via a fragmentation function that in principle may be independently obtained from e+e− annihilation data. Results are presented, discussed and compared to existing measurements as well as to model predictions. Asymmetries of π+π− pairs measured with the proton target as a function of the Bjorken scaling variable are sizeable in the range x>0.032, indicating non-vanishing transversity distribution and di-hadron interference fragmentation functions. As already pointed out by several authors, the small asymmetries of π+π− measured on the 6LiD target can be interpreted as indication for a cancellation of u and d-quark transversity distributions.
Published: 2023
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4. Modulation of the seasonal cycle of the Antarctic sea ice extent by sea ice processes and feedbacks with the ocean and the atmosphere

Author: H. Goosse, S. Allende Contador, C. M. Bitz, E. Blanchard-Wrigglesworth, C. Eayrs, T. Fichefet, K. Himmich, P.-V. Huot, F. Klein, S. Marchi, F. Massonnet, B. Mezzina, C. Pelletier, L. Roach, M. Vancoppenolle, and N. P. M. van Lipzig
Subjects: Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract: The seasonal cycle of the Antarctic sea ice extent is strongly asymmetric, with a relatively slow increase after the summer minimum followed by a more rapid decrease after the winter maximum. This cycle is intimately linked to the seasonal cycle of the insolation received at the top of the atmosphere, but sea ice processes as well as the exchanges with the atmosphere and ocean may also play a role. To quantify these contributions, a series of idealized sensitivity experiments have been performed with an eddy-permitting (1/4∘) NEMO-LIM3 (Nucleus for European Modelling of the Ocean–Louvain-la-Neuve sea ice model version 3) Southern Ocean configuration, including a representation of ice shelf cavities, in which the model was either driven by an atmospheric reanalysis or coupled to the COSMO-CLM2 regional atmospheric model. In those experiments, sea ice thermodynamics and dynamics as well as the exchanges with the ocean and atmosphere are strongly perturbed. This perturbation is achieved by modifying snow and ice thermal conductivities, the vertical mixing in the ocean top layers, the effect of freshwater uptake and release upon sea ice growth and melt, ice dynamics, and surface albedo. We find that the evolution of sea ice extent during the ice advance season is largely independent of the direct effect of the perturbation and appears thus mainly controlled by initial state in summer and subsequent insolation changes. In contrast, the melting rate varies strongly between the experiments during the retreat, in particular if the surface albedo or sea ice transport are modified, demonstrating a strong contribution of those elements to the evolution of ice coverage through spring and summer. As with the advance phase, the retreat is also influenced by conditions at the beginning of the melt season in September. Atmospheric feedbacks enhance the model winter ice extent response to any of the perturbed processes, and the enhancement is strongest when the albedo is modified. The response of sea ice volume and extent to changes in entrainment of subsurface warm waters to the ocean surface is also greatly amplified by the coupling with the atmosphere.
Published: 2023
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5. Using a process-based dendroclimatic proxy system model in a data assimilation framework: a test case in the Southern Hemisphere over the past centuries

Author: J. Rezsöhazy, Q. Dalaiden, F. Klein, H. Goosse, and J. Guiot
Subjects: Environmental pollution, TD172-193.5, Environmental protection, TD169-171.8, Environmental sciences, GE1-350
Abstract: Currently available data-assimilation-based reconstructions of past climate variations have only used statistical proxy system models to make the link between climate model outputs and indirect observations from tree rings. However, the linearity and stationarity assumptions of the statistical approach may have limitations. In this study, we incorporate the process-based dendroclimatic model MAIDEN into a data assimilation procedure using the reconstruction of near-surface air temperature, precipitation and winds in the midlatitudes of the Southern Hemisphere over the past 400 years as a test case. We compare our results with a data assimilation approach including a linear regression as a proxy system model for tree-ring width proxies. Overall, when compared to instrumental data, the reconstructions using MAIDEN as a proxy system model offer a skill equivalent to the experiment using the regression model. However, knowing the advantages that a process-based model can bring and the improvements that can still be made with MAIDEN, those results are promising.
Published: 2022
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6. Collins and Sivers transverse-spin asymmetries in inclusive muoproduction of ρ0 mesons

Author: G.D. Alexeev, M.G. Alexeev, C. Alice, A. Amoroso, V. Andrieux, V. Anosov, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badelek, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, M. Bodlak, F. Bradamante, A. Bressan, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, P.M.M. Correia, M.L. Crespo, D. D'Ago, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, F. Del Carro, I. Denisenko, O.Yu. Denisov, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, D. Ecker, A. Efremov, C. Elia, D. Eremeev, P. Faccioli, M. Faessler, M. Finger, M. Finger, jr., H. Fischer, K.J. Flöthner, W. Florian, J.M. Friedrich, V. Frolov, L.G. Garcia Ordòñez, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, D. Giordano, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, M. Grüner, A. Guskov, D. von Harrach, M. Hoffmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, A. Khatun, G.V. Khaustov, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Korzenev, A.M. Kotzinian, O.M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, K. Lavickova, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, A. Maltsev, S.A. Mamon, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, C. Menezes Pires, F. Metzger, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, D. Miura, Y. Miyachi, R. Molina, A. Moretti, A. Nagaytsev, C. Naim, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, H. Pekeler, J.-C. Peng, M. Pešek, D.V. Peshekhonov, M. Pešková, S. Platchkov, J. Pochodzalla, V.A. Polyakov, M. Quaresma, C. Quintans, G. Reicherz, C. Riedl, T. Rudnicki, D.I. Ryabchikov, A. Rychter, A. Rymbekova, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, K. Sharko, L. Sinha, M. Slunecka, F. Sozzi, D. Spülbeck, A. Srnka, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, T. Triloki, V. Tskhay, B. Valinoti, B.M. Veit, J.F.C.A. Veloso, B. Ventura, M. Virius, M. Wagner, S. Wallner, K. Zaremba, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, and M. Ziembicki
Subjects: SIDIS, Spin, Fragmentation, Collins asymmetry, Sivers asymmetry, Physics, QC1-999
Abstract: The production of vector mesons in deep inelastic scattering is an interesting yet scarcely explored channel to study the transverse spin structure of the nucleon and the spin-dependence of fragmentation. The COMPASS collaboration has performed the first measurement of the Collins and Sivers asymmetries for inclusively produced ρ0 mesons. The analysis is based on the data set collected in deep inelastic scattering in 2010 using a 160GeV/c μ+ beam impinging on a transversely polarized NH3 target. The ρ0 mesons are selected from oppositely charged hadron pairs, and the asymmetries are extracted as a function of the Bjorken-x variable, the transverse momentum of the pair and the fraction of the energy z carried by the pair. Indications for positive Collins and Sivers asymmetries are observed.
Published: 2023
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7. Double J/ψ production in pion-nucleon scattering at COMPASS

Author: G.D. Alexeev, M.G. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badełek, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, M. Bodlak, F. Bradamante, A. Bressan, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, P.M.M. Correia, M.L. Crespo, D. D'Ago, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, I. Denisenko, O.Yu. Denisov, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, D. Ecker, A. Efremov, D. Eremeev, P.D. Eversheim, P. Faccioli, M. Faessler, M. Finger, M. Finger, jr., H. Fischer, K.J. Flöthner, W. Florian, C. Franco, J.M. Friedrich, V. Frolov, L.G. Garcia Ordòñez, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, D. Giordano, M. Gorzellik, A. Grasso, A. Gridin, S. Groote, M. Grosse Perdekamp, B. Grube, M. Grüner, A. Guskov, D. von Harrach, M. Hoffmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, A. Khatun, G.V. Khaustov, Yu.A. Khokhlov, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Korzenev, S. Koshkarev, A.M. Kotzinian, O.M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, K. Lavickova, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, A. Maltsev, S.A. Mamon, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, C. Menezes Pires, F. Metzger, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, Y. Miyachi, R. Molina, A. Moretti, A. Nagaytsev, C. Naim, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, H. Pekeler, J.-C. Peng, M. Pešek, D.V. Peshekhonov, M. Pešková, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, G. Reicherz, C. Riedl, T. Rudnicki, D.I. Ryabchikov, A. Rychter, A. Rymbekova, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, K. Sharko, L. Sinha, M. Slunecka, D. Spülbeck, A. Srnka, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, T. Triloki, V. Tskhay, B. Valinoti, B.M. Veit, J.F.C.A. Veloso, B. Ventura, M. Virius, M. Wagner, S. Wallner, K. Zaremba, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, and M. Ziembicki
Subjects: COMPASS, Charmonia production, Double J/ψ, Single parton scattering, Intrinsic charm, Physics, QC1-999
Abstract: We present the study of the production of double J/ψ mesons using COMPASS data collected with a 190 GeV/c π− beam scattering off NH3, Al and W targets. Kinematic distributions of the collected double J/ψ events are analysed, and the double J/ψ production cross section is estimated for each of the COMPASS targets. The NH3 results are compared to predictions from single- and double-parton scattering models as well as the pion intrinsic charm and the tetraquark exotic resonance hypotheses. It is demonstrated that the single parton scattering production mechanism gives the dominant contribution that is sufficient to describe the data. An upper limit on the double intrinsic charm content of the pion is evaluated. No significant signatures that could be associated with exotic tetraquarks are found in the double J/ψ mass spectrum.
Published: 2023
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8. PARASO, a circum-Antarctic fully coupled ice-sheet–ocean–sea-ice–atmosphere–land model involving f.ETISh1.7, NEMO3.6, LIM3.6, COSMO5.0 and CLM4.5

Author: C. Pelletier, T. Fichefet, H. Goosse, K. Haubner, S. Helsen, P.-V. Huot, C. Kittel, F. Klein, S. Le clec'h, N. P. M. van Lipzig, S. Marchi, F. Massonnet, P. Mathiot, E. Moravveji, E. Moreno-Chamarro, P. Ortega, F. Pattyn, N. Souverijns, G. Van Achter, S. Vanden Broucke, A. Vanhulle, D. Verfaillie, and L. Zipf
Subjects: Geology, QE1-996.5
Abstract: We introduce PARASO, a novel five-component fully coupled regional climate model over an Antarctic circumpolar domain covering the full Southern Ocean. The state-of-the-art models used are the fast Elementary Thermomechanical Ice Sheet model (f.ETISh) v1.7 (ice sheet), the Nucleus for European Modelling of the Ocean (NEMO) v3.6 (ocean), the Louvain-la-Neuve sea-ice model (LIM) v3.6 (sea ice), the COnsortium for Small-scale MOdeling (COSMO) model v5.0 (atmosphere) and its CLimate Mode (CLM) v4.5 (land), which are here run at a horizontal resolution close to 1/4∘. One key feature of this tool resides in a novel two-way coupling interface for representing ocean–ice-sheet interactions, through explicitly resolved ice-shelf cavities. The impact of atmospheric processes on the Antarctic ice sheet is also conveyed through computed COSMO-CLM–f.ETISh surface mass exchange. In this technical paper, we briefly introduce each model's configuration and document the developments that were carried out in order to establish PARASO. The new offline-based NEMO–f.ETISh coupling interface is thoroughly described. Our developments also include a new surface tiling approach to combine open-ocean and sea-ice-covered cells within COSMO, which was required to make this model relevant in the context of coupled simulations in polar regions. We present results from a 2000–2001 coupled 2-year experiment. PARASO is numerically stable and fully operational. The 2-year simulation conducted without fine tuning of the model reproduced the main expected features, although remaining systematic biases provide perspectives for further adjustment and development.
Published: 2022
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9. Fluid‐Mediated Mass Transfer Between Mafic and Ultramafic Rocks in Subduction Zones

Author: E. A. Codillo, F. Klein, B. Dragovic, H. R. Marschall, E. Baxter, M. Scambelluri, and E. Schwarzenbach‬
Subjects: fluid‐rock interactions, magnesium metasomatism, subduction zones, Voltri Massif, Geophysics. Cosmic physics, QC801-809, Geology, QE1-996.5
Abstract: Abstract Metasomatic reaction zones between mafic and ultramafic rocks exhumed from subduction zones provide a window into mass‐transfer processes at high pressure. However, accurate interpretation of the rock record requires distinguishing high‐pressure metasomatic processes from inherited oceanic signatures prior to subduction. We integrated constraints from bulk‐rock geochemical compositions and petrophysical properties, mineral chemistry, and thermodynamic modeling to understand the formation of reaction zones between juxtaposed metagabbro and serpentinite as exemplified by the Voltri Massif (Ligurian Alps, Italy). Distinct zones of variably metasomatized metagabbro are dominated by chlorite, amphibole, clinopyroxene, epidote, rutile, ilmenite, and titanite between serpentinite and eclogitic metagabbro. Whereas the precursor serpentinite and oxide gabbro formed and were likely already in contact in an oceanic setting, the reaction zones formed by diffusional Mg‐metasomatism between the two rocks from prograde to peak, to retrograde conditions in a subduction zone. Metasomatism of mafic rocks by Mg‐rich fluids that previously equilibrated with serpentinite could be widespread along the subduction interface, within the subducted slab, and the mantle wedge. Furthermore, the models predict that talc formation by Si‐metasomatism of serpentinite in subduction zones is limited by pressure‐dependent increase in the silica activity buffered by the serpentine‐talc equilibrium. Elevated activities of aqueous Ca and Al species would also favor the formation of chlorite and garnet. Accordingly, unusual conditions or processes would be required to stabilize abundant talc at high P‐T conditions. Alternatively, a different set of mineral assemblages, such as serpentine‐ or chlorite‐rich rocks, may be controlling the coupling‐decoupling transition of the plate interface.
Published: 2022
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10. Workshop report: Exploring deep oceanic crust off Hawai`i

Author: S. Umino, G. F. Moore, B. Boston, R. Coggon, L. Crispini, S. D'Hondt, M. O. Garcia, T. Hanyu, F. Klein, N. Seama, D. A. H. Teagle, M. Tominaga, M. Yamashita, M. Harris, B. Ildefonse, I. Katayama, Y. Kusano, Y. Suzuki, E. Trembath-Reichert, Y. Yamada, N. Abe, N. Xiao, and F. Inagaki
Subjects: Geology, QE1-996.5
Abstract: For more than half a century, exploring a complete sequence of the oceanic crust from the seafloor through the Mohorovičić discontinuity (Moho) and into the uppermost mantle has been one of the most challenging missions of scientific ocean drilling. Such a scientific and technological achievement would provide humankind with profound insights into the largest realm of our planet and expand our fundamental understanding of Earth's deep interior and its geodynamic behavior. The formation of new oceanic crust at mid-ocean ridges and its subsequent aging over millions of years, leading to subduction, arc volcanism, and recycling of some components into the mantle, comprise the dominant geological cycle of matter and energy on Earth. Although previous scientific ocean drilling has cored some drill holes into old (> 110 Ma) and young (< 20 Ma) ocean crust, our sampling remains relatively shallow (< 2 km into intact crust) and unrepresentative of average oceanic crust. To date, no hole penetrates more than 100 m into intact average-aged oceanic crust that records the long-term history of seawater–basalt exchange (60 to 90 Myr). In addition, the nature, extent, and evolution of the deep subseafloor biosphere within oceanic crust remains poorly unknown. To address these fundamentally significant scientific issues, an international workshop “Exploring Deep Oceanic Crust off Hawai`i” brought together 106 scientists and engineers from 16 countries that represented the entire spectrum of disciplines, including petrologists, geophysicists, geochemists, microbiologists, geodynamic modelers, and drilling/logging engineers. The aim of the workshop was to develop a full International Ocean Discovery Program (IODP) proposal to drill a 2.5 km deep hole into oceanic crust on the North Arch off Hawai`i with the drilling research vessel Chikyu. This drill hole would provide samples down to cumulate gabbros of mature (∼ 80 Ma) oceanic crust formed at a half spreading rate of ∼ 3.5 cm a−1. A Moho reflection has been observed at ∼ 5.5 km below the seafloor at this site, and the workshop concluded that the proposed 2.5 km deep scientific drilling on the North Arch off Hawai`i would provide an essential “pilot hole” to inform the design of future mantle drilling.
Published: 2021
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11. Spin density matrix elements in exclusive $$\omega $$ ω meson muoproduction

Author: G. D. Alexeev, M. G. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, C. D. R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Berenguer Antequera, J. Bernhard, M. Bodlak, F. Bradamante, A. Bressan, V. E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A. G. Chumakov, S.-U. Chung, A. Cicuttin, P. M. M. Correia, M. L. Crespo, D. D’Ago, S. Dalla Torre, S. S. Dasgupta, S. Dasgupta, I. Denisenko, O. Yu. Denisov, S. V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R. R. Dusaev, A. Efremov, P. D. Eversheim, P. Faccioli, M. Faessler, A. Ferrero, M. Finger, H. Fischer, C. Franco, J. M. Friedrich, V. Frolov, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d’Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, P. Jörg, R. Joosten, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, G. V. Khaustov, Yu. A. Khokhlov, Yu. Kisselev, F. Klein, J. H. Koivuniemi, V. N. Kolosov, K. Kondo Horikawa, I. Konorov, V. F. Konstantinov, A. M. Kotzinian, O. M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, Y. Kulinich, F. Kunne, K. Kurek, R. P. Kurjata, A. Kveton, K. Lavickova, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V. E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G. K. Mallot, A. Maltsev, S. A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, G. V. Meshcheryakov, M. Meyer, W. Meyer, Yu. V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, C. Naim, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A. S. Nunes, A. G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, H. Pekeler, J.-C. Peng, M. Pešek, D. V. Peshekhonov, M. Pešková, N. Pierre, S. Platchkov, J. Pochodzalla, V. A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, C. Regali, G. Reicherz, C. Riedl, T. Rudnicki, D. I. Ryabchikov, A. Rybnikov, A. Rychter, V. D. Samoylenko, A. Sandacz, S. Sarkar, I. A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, L. Sinha, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, T. Szameitat, P. Sznajder, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, V. Tskhay, S. Uhl, B. I. Vasilishin, A. Vauth, B. M. Veit, J. Veloso, B. Ventura, A. Vidon, M. Virius, M. Wagner, S. Wallner, K. Zaremba, P. Zavada, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, Y. Zhao, M. Ziembicki, and COMPASS Collaboration
Subjects: Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Abstract We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $$\omega $$ ω meson muoproduction on the proton at COMPASS using 160 GeV/c polarised $$ \mu ^{+}$$ μ + and $$ \mu ^{-}$$ μ - beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/ $$c^2$$ c 2 $$< W
Published: 2021
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12. How useful is snow accumulation in reconstructing surface air temperature in Antarctica? A study combining ice core records and climate models

Author: Q. Dalaiden, H. Goosse, F. Klein, J. T. M. Lenaerts, M. Holloway, L. Sime, and E. R. Thomas
Subjects: Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract: Improving our knowledge of the temporal and spatial variability of the Antarctic Ice Sheet (AIS) surface mass balance (SMB) is crucial to reduce the uncertainties of past, present, and future Antarctic contributions to sea level rise. An examination of the surface air temperature–SMB relationship in model simulations demonstrates a strong link between the two. Reconstructions based on ice cores display a weaker relationship, indicating a model–data discrepancy that may be due to model biases or to the non-climatic noise present in the records. We find that, on the regional scale, the modeled relationship between surface air temperature and SMB is often stronger than between temperature and δ18O. This suggests that SMB data can be used to reconstruct past surface air temperature. Using this finding, we assimilate isotope-enabled SMB and δ18O model output with ice core observations to generate a new surface air temperature reconstruction. Although an independent evaluation of the skill is difficult because of the short observational time series, this new reconstruction outperforms the previous reconstructions for the continental-mean temperature that were based on δ18O alone. The improvement is most significant for the East Antarctic region, where the uncertainties are particularly large. Finally, using the same data assimilation method as for the surface air temperature reconstruction, we provide a spatial SMB reconstruction for the AIS over the last 2 centuries, showing large variability in SMB trends at a regional scale, with an increase (0.82 Gt yr−2) in West Antarctica over 1957–2000 and a decrease in East Antarctica during the same period (−0.13 Gt yr−2). As expected, this is consistent with the recent reconstruction used as a constraint in the data assimilation.
Published: 2020
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13. Probing transversity by measuring Λ polarisation in SIDIS

Author: G.D. Alexeev, M.G. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Berenguer Antequera, J. Bernhard, M. Bodlak, F. Bradamante, A. Bressan, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, P.M.M. Correia, M.L. Crespo, D. D'Ago, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, I. Denisenko, O.Yu. Denisov, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, A. Efremov, C. Elia, D. Eremeev, P.D. Eversheim, P. Faccioli, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, K.J. Flöthner, C. Franco, J.M. Friedrich, V. Frolov, L.G. Garcia Ordòñez, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, D. Giordano, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. von Harrach, R. Heitz, M. Hoffmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, E. Kabuß, D.-H. Kang, F. Kaspar, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, K. Lavickova, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, A. Maltsev, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, G.V. Meshcheryakov, F. Metzger, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, C. Naim, T.S. Negrini, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, H. Pekeler, J.-C. Peng, M. Pešek, D.V. Peshekhonov, M. Pešková, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, G. Reicherz, C. Riedl, T. Rudnicki, D.I. Ryabchikov, A. Rychter, A. Rymbekova, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, H. Schmieden, A. Selyunin, K. Sharko, L. Sinha, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, P. Sznajder, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, B. Ventura, A. Vidon, M. Virius, M. Wagner, S. Wallner, K. Zaremba, P. Zavada, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, Y. Zhao, and M. Ziembicki
Subjects: Quantum chromodynamics, Deep inelastic scattering, Lambda polarisation, Transversity, COMPASS, Physics, QC1-999
Abstract: Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions h1q are nowadays well established. Several possible channels to access these functions were originally proposed. One candidate is the measurement of the polarisation of Λ hyperons produced in SIDIS off transversely polarised nucleons, where the transverse polarisation of the struck quark might be transferred to the final-state hyperon. In this article, we present the COMPASS results on the transversity-induced polarisation of Λ and Λ¯ hyperons produced in SIDIS off transversely polarised protons. Within the experimental uncertainties, no significant deviation from zero was observed. The results are discussed in the context of different models taking into account previous experimental results on h1u and h1d.
Published: 2022
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14. Workshop report on hard-rock drilling into mid-Cretaceous Pacific oceanic crust on the Hawaiian North Arch

Author: T. Morishita, S. Umino, J.-I. Kimura, M. Yamashita, S. Ono, K. Michibayashi, M. Tominaga, F. Klein, and M. O. Garcia
Subjects: Geology, QE1-996.5
Abstract: The architecture, formation, and modification of oceanic plates are fundamental to our understanding of key geologic processes of the Earth. Geophysical surveys were conducted around a site near the Hawaiian Islands (northeastern Hawaiian North Arch region; Hawaiian North Arch hereafter), which is one of three potential sites for an International Ocean Discovery Program mantle drilling proposal for the Pacific plate that was submitted in 2012. The Hawaiian North Arch site is located in 78–81 Ma Cretaceous crust, which had an estimated full spreading rate of 7–8 cm yr−1. This site fills a major gap in our understanding of oceanic crust. Previously drilling has been skewed to young or older crust ( or >110 Ma) and slow-spread crust. P-wave velocity structure in the uppermost mantle of the Hawaiian North Arch shows a strong azimuthal anisotropy, whereas Moho reflections below the basement are variable: strong and continuous, weak, diffuse, or unclear. We assume that the strength of the Moho reflection is related to the aging of the oceanic plate. The Hawaiian volcanic chain (200 km to the southwest of the proposed drill site) and the nearby North Arch magmatism on the proposed Hawaiian North Arch sites might also have affected recognition of the Moho via deformation and/or magma intrusion into the lower crust of the uppermost mantle. This workshop report describes scientific targets for 2 km deep-ocean drilling in the Hawaiian North Arch region in order to provide information about the lower crust from unrecovered age and spreading rate gaps from previous ocean drillings. Other scientific objectives to be achieved by drilling cores before reaching the target depth of the project are also described in this report.
Published: 2019
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15. Erratum to: Azimuthal asymmetries of charged hadrons produced in high-energy muon scattering off longitudinally polarised deuterons

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M. G. Alexeev, G. D. Alexeev, A. Amoroso, V. Andrieux, N. V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C. D. R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E. R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M. L. Crespo, Q. Curiel, S. Dalla Torre, S. S. Dasgupta, S. Dasgupta, O. Yu. Denisov, L. Dhara, S. V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P. D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, H. Fischer, C. Franco, N. du Fresne von Hohenesche, J. M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F. H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d’Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G. V. Khaustov, Yu. A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J. H. Koivuniemi, V. N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V. F. Konstantinov, A. M. Kotzinian, O. M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z. V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R. P. Kurjata, A. A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G. K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G. V. Meshcheryakov, M. Meyer, W. Meyer, Yu. V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A. S. Nunes, A. G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D. V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V. A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N. S. Rossiyskaya, D. I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V. D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I. A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink
Subjects: Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: The original version of this article unfortunately contained a mistake.
Published: 2020
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16. Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section

Author: R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, E. Burtin, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, K. Juraskova, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, A. Vidon, M. Virius, S. Wallner, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, and M. Ziembicki
Subjects: Physics, QC1-999
Abstract: We report on the first measurement of exclusive single-photon muoproduction on the proton by COMPASS using 160GeV/c polarised μ+ and μ− beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average of the measured μ+ and μ− cross sections for deeply virtual Compton scattering on the squared four-momentum transfer t from the initial to the final proton. The slope B of the t-dependence is fitted with a single exponential function, which yields B=(4.3±0.6stat|sys−0.3+0.1)(GeV/c)−2. This result can be converted into a transverse extension of partons in the proton, 〈r⊥2〉=(0.58±0.04stat|sys−0.02+0.01±0.04model)fm. For this measurement, the average virtuality of the photon mediating the interaction is 〈Q2〉=1.8(GeV/c)2 and the average value of the Bjorken variable is 〈xBj〉=0.056. Keywords: Quantum chromodynamics, Deep inelastic scattering, Exclusive reactions, Deeply virtual Compton scattering, Generalized Parton Distributions, Proton size, COMPASS
Published: 2019
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17. Fluid–rock interactions in the shallow Mariana forearc: carbon cycling and redox conditions

Author: E. Albers, W. Bach, F. Klein, C. D. Menzies, F. Lucassen, and D. A. H. Teagle
Subjects: Geology, QE1-996.5, Stratigraphy, QE640-699
Abstract: Few data exist that provide insight into processes affecting the long-term carbon cycle at shallow forearc depths. To better understand the mobilization of C in sediments and crust of the subducting slab, we investigated carbonate materials that originate from the subduction channel at the Mariana forearc (87Sr∕86Sr = 0.7052 to 0.7054, δ18OVSMOW = 20 to 24 ‰) imply precipitation from slab-derived fluids at temperatures between ∼130 and 300 ∘C. These temperature estimates are consistent with the presence of blueschist facies phases such as lawsonite coexisting with the carbonates in some veins. Incorporated C is inorganic (δ13CVPDB = −1 ‰ to +4 ‰) and likely derived from the decarbonation of calcareous sediment and/or oceanic crust. These findings provide evidence for the mobilization of C in the downgoing slab at depths of
Published: 2019
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18. Assessing the robustness of Antarctic temperature reconstructions over the past 2 millennia using pseudoproxy and data assimilation experiments

Author: F. Klein, N. J. Abram, M. A. J. Curran, H. Goosse, S. Goursaud, V. Masson-Delmotte, A. Moy, R. Neukom, A. Orsi, J. Sjolte, N. Steiger, B. Stenni, and M. Werner
Subjects: Environmental pollution, TD172-193.5, Environmental protection, TD169-171.8, Environmental sciences, GE1-350
Abstract: The Antarctic temperature changes over the past millennia remain more uncertain than in many other continental regions. This has several origins: (1) the number of high-resolution ice cores is small, in particular on the East Antarctic plateau and in some coastal areas in East Antarctica; (2) the short and spatially sparse instrumental records limit the calibration period for reconstructions and the assessment of the methodologies; (3) the link between isotope records from ice cores and local climate is usually complex and dependent on the spatial scales and timescales investigated. Here, we use climate model results, pseudoproxy experiments and data assimilation experiments to assess the potential for reconstructing the Antarctic temperature over the last 2 millennia based on a new database of stable oxygen isotopes in ice cores compiled in the framework of Antarctica2k (Stenni et al., 2017). The well-known covariance between δ18O and temperature is reproduced in the two isotope-enabled models used (ECHAM5/MPI-OM and ECHAM5-wiso), but is generally weak over the different Antarctic regions, limiting the skill of the reconstructions. Furthermore, the strength of the link displays large variations over the past millennium, further affecting the potential skill of temperature reconstructions based on statistical methods which rely on the assumption that the last decades are a good estimate for longer temperature reconstructions. Using a data assimilation technique allows, in theory, for changes in the δ18O–temperature link through time and space to be taken into account. Pseudoproxy experiments confirm the benefits of using data assimilation methods instead of statistical methods that provide reconstructions with unrealistic variances in some Antarctic subregions. They also confirm that the relatively weak link between both variables leads to a limited potential for reconstructing temperature based on δ18O. However, the reconstruction skill is higher and more uniform among reconstruction methods when the reconstruction target is the Antarctic as a whole rather than smaller Antarctic subregions. This consistency between the methods at the large scale is also observed when reconstructing temperature based on the real δ18O regional composites of Stenni et al. (2017). In this case, temperature reconstructions based on data assimilation confirm the long-term cooling over Antarctica during the last millennium, and the later onset of anthropogenic warming compared with the simulations without data assimilation, which is especially visible in West Antarctica. Data assimilation also allows for models and direct observations to be reconciled by reproducing the east–west contrast in the recent temperature trends. This recent warming pattern is likely mostly driven by internal variability given the large spread of individual Paleoclimate Modelling Intercomparison Project (PMIP)/Coupled Model Intercomparison Project (CMIP) model realizations in simulating it. As in the pseudoproxy framework, the reconstruction methods perform differently at the subregional scale, especially in terms of the variance of the time series produced. While the potential benefits of using a data assimilation method instead of a statistical method have been highlighted in a pseudoproxy framework, the instrumental series are too short to confirm this in a realistic setup.
Published: 2019
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19. Measurement of PT-weighted Sivers asymmetries in leptoproduction of hadrons

Author: M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, V. Barone, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, P. Jörg, K. Juraskova, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, A.A. Lednev, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, H. Schmieden, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, A. Vidon, M. Virius, M. Wagner, S. Wallner, M. Wilfert, K. Zaremba, P. Zavada, M. Zavertyaev, Y. Zhao, E. Zemlyanichkina, and M. Ziembicki
Subjects: Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: The transverse spin asymmetries measured in semi-inclusive leptoproduction of hadrons, when weighted with the hadron transverse momentum PT, allow for the extraction of important transverse-momentum-dependent distribution functions. In particular, the weighted Sivers asymmetries provide direct information on the Sivers function, which is a leading-twist distribution that arises from a correlation between the transverse momentum of an unpolarised quark in a transversely polarised nucleon and the spin of the nucleon. Using the high-statistics data collected by the COMPASS Collaboration in 2010 with a transversely polarised proton target, we have evaluated two types of PT-weighted Sivers asymmetries, which are both proportional to the product of the first transverse moment of the Sivers function and of the fragmentation function. The results are compared to the standard unweighted Sivers asymmetries and used to extract the first transverse moments of the Sivers distributions for u and d quarks.
Published: 2019
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20. Corrigendum to 'Odd and even partial waves of ηπ− and η′π− in π−p → η(′)π−p at 191 GeV/c' [Phys. Lett. B 740 (2015) 303–311]

Author: C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, A. Berlin, J. Bernhard, K. Bicker, E.R. Bielert, J. Bieling, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, L. Capozza, M. Chiosso, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, R. Geyer, I. Gnesi, B. Gobbo, S. Goertz, M. Gorzellik, S. Grabmüller, A. Grasso, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. von Harrach, D. Hahne, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, Ch. Höppner, N. Horikawa, N. d'Hose, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jasinski, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, A. Maggiora, A. Magnon, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, M. Mikhasenko, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, S. Neubert, D. Neyret, J. Novy, W.-D. Nowak, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, E. Rocco, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, M. Schott, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, S. Sosio, F. Sozzi, A. Srnka, L. Steiger, M. Stolarski, M. Sulc, R. Sulej, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, S. Uhl, I. Uman, M. Virius, L. Wang, T. Weisrock, M. Wilfert, R. Windmolders, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink
Subjects: Physics, QC1-999
Abstract: In Fig. 5 on p. 311 of our Phys. Lett. B 740 (2015) 303 an adjustment by 180∘ is required for the phases with respect to the L=2,M=1 wave, of the following waves: L=1,3,5 with M=1, and L=2 with M=2. After this correction (Fig. 5 (corrected) below), the extracted partial waves describe the angular distribution of the η(′) in the Gottfried-Jackson (GJ) frame, using Eq. (4) with implicit Condon-Shortley phase convention. The other results of our paper are not affected. The right-handed GJ coordinate system was defined by the z-axis pointing in the direction of the beam in the η(′)π− center-of-mass system and the y-axis pointing in the direction of precoilGJ×pbeamGJ.
Published: 2020
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21. Antiproton over proton and K− over K+ multiplicity ratios at high z in DIS

Author: G.D. Alexeev, M.G. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Berenguer Antequera, J. Bernhard, M. Bodlak, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, P.M.M. Correia, M.L. Crespo, D. D'Ago, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, I. Denisenko, O.Yu. Denisov, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, A. Efremov, P.D. Eversheim, P. Faccioli, M. Faessler, M. Finger, M. Finger, jr., H. Fischer, C. Franco, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, P. Jörg, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, K. Lavičková, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, A. Maltsev, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, C. Naim, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, H. Pekeler, J.-C. Peng, M. Pešek, D.V. Peshekhonov, M. Pešková, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, G. Reicherz, C. Riedl, T. Rudnicki, D.I. Ryabchikov, A. Rybnikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, L. Sinha, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, P. Sznajder, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, B. Ventura, A. Vidon, M. Virius, M. Wagner, S. Wallner, K. Zaremba, P. Zavada, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, Y. Zhao, and M. Ziembicki
Subjects: Quantum chromodynamics, pQCD, Deep-inelastic scattering, Hadron multiplicities, COMPASS, Physics, QC1-999
Abstract: The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar 6LiD target. The regime of deep-inelastic scattering is ensured by requiring Q2 > 1 (GeV/c)2 for the photon virtuality and W>5 GeV/c2 for the invariant mass of the produced hadronic system. Bjorken-x is restricted to the range 0.01 to 0.40. Protons and antiprotons are identified in the momentum range from 20 GeV/c to 60 GeV/c and required to carry a large fraction of the virtual-photon energy, z>0.5. In the whole studied z-region, the p¯ over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Kaons were previously analysed in the momentum range 12 GeV/c to 40 GeV/c. In the present analysis this range is extended up to 55 GeV/c, whereby events with larger virtual-photon energies are included in the analysis and the observed K− over K+ ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that at COMPASS energies the phase space available for single-hadron production in deep-inelastic scattering should be taken into account in the standard pQCD formalism.
Published: 2020
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22. Contribution of exclusive diffractive processes to the measured azimuthal asymmetries in SIDIS

Author: J. Agarwala, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Berenguer Antequera, J. Bernhard, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, P.M.M. Correia, M.L. Crespo, D. D'Ago, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, I. Denisenko, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, P. Jörg, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, A. Koval, Z. Kral, F. Krinner, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, K. Lavickova, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, A. Maltsev, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G. Mattson, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, C. Naim, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, H. Pekeler, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, M. Pešková, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, G. Reicherz, C. Riedl, T. Rudnicki, D.I. Ryabchikov, A. Rybnikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, L. Sinha, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, P. Sznajder, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, A. Townsend, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, B. Ventura, A. Vidon, M. Virius, M. Wagner, S. Wallner, M. Wilfert, K. Zaremba, P. Zavada, M. Zavertyaev, M. Zemko, E. Zemlyanichkina, Y. Zhao, and M. Ziembicki
Subjects: Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Hadron leptoproduction in Semi-Inclusive measurements of Deep-Inelastic Scattering (SIDIS) on unpolarised nucleons allows one to get information on the intrinsic transverse momentum of quarks in a nucleon and on the Boer-Mulders function through the measurement of azimuthal modulations in the cross section. These modulations were recently measured by the HERMES experiment at DESY on proton and deuteron targets, and by the COMPASS experiment using the CERN SPS muon beam and a 6LiD target. In both cases, the amplitudes of the cos⁡ϕh and cos⁡2ϕh modulations show strong kinematic dependences for both positive and negative hadrons. It has been known since some time that the measured final-state hadrons in those SIDIS experiments receive a contribution from exclusive diffractive production of vector mesons, particularly important at large values of z, the fraction of the virtual photon energy carried by the hadron. In previous measurements of azimuthal asymmetries this contribution was not taken into account, because it was not known that it could distort the azimuthal modulations. Presently, a method to evaluate the contribution of the exclusive reactions to the azimuthal asymmetries measured by COMPASS has been developed. The subtraction of this contribution results in a better understanding of the kinematic effects, and the remaining non-zero cos⁡2ϕh modulation gives indication for a non-zero Boer-Mulders effect.
Published: 2020
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23. Measurement of the cross section for hard exclusive π0 muoproduction on the proton

Author: M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, P. Jörg, K. Juraskova, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, C. Naim, A. Nagaytsev, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, M. Pešková, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, D.I. Ryabchikov, A. Rybnikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, L. Silva, L. Sinha, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, A. Vidon, M. Virius, M. Wagner, S. Wallner, M. Wilfert, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, Y. Zhao, and M. Ziembicki
Subjects: Quantum chromodynamics, Muoproduction, Hard exclusive meson production, Generalised Parton Distributions, COMPASS, Physics, QC1-999
Abstract: We report on a measurement of hard exclusive π0 muoproduction on the proton by COMPASS using 160GeV/c polarised μ+ and μ− beams of the CERN SPS impinging on a liquid hydrogen target. From the average of the measured μ+ and μ− cross sections, the virtual-photon proton cross section is determined as a function of the squared four-momentum transfer between initial and final proton in the range 0.08(GeV/c)2
Published: 2020
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24. New data on γ→p→→ηp with polarized photons and protons and their implications for N⁎ → Nη decays

Author: J. Müller, J. Hartmann, M. Grüner, F. Afzal, A.V. Anisovich, B. Bantes, D. Bayadilov, R. Beck, M. Becker, Y. Beloglazov, A. Berlin, M. Bichow, S. Böse, K.-T. Brinkmann, T. Challand, V. Crede, F. Dietz, M. Dieterle, P. Drexler, H. Dutz, H. Eberhardt, D. Elsner, R. Ewald, K. Fornet-Ponse, S. Friedrich, F. Frommberger, C. Funke, M. Gottschall, A. Gridnev, S. Goertz, E. Gutz, C. Hammann, V. Hannen, J. Hannappel, J. Herick, W. Hillert, P. Hoffmeister, C. Honisch, O. Jahn, T. Jude, I. Jaegle, A. Käser, D. Kaiser, H. Kalinowsky, F. Kalischewski, S. Kammer, I. Keshelashvili, P. Klassen, V. Kleber, F. Klein, E. Klempt, K. Koop, B. Krusche, M. Kube, M. Lang, I. Lopatin, Y. Maghrbi, P. Mahlberg, K. Makonyi, F. Messi, V. Metag, W. Meyer, J. Müllers, M. Nanova, V. Nikonov, D. Novinski, R. Novotny, D. Piontek, G. Reicherz, C. Rosenbaum, T. Rostomyan, B. Roth, A. Sarantsev, C. Schmidt, H. Schmieden, R. Schmitz, T. Seifen, V. Sokhoyan, A. Thiel, U. Thoma, M. Urban, H. van Pee, D. Walther, C. Wendel, U. Wiedner, A. Wilson, A. Winnebeck, and L. Witthauer
Subjects: Physics, QC1-999
Abstract: The polarization observables T,E,P,H, and G in photoproduction of η mesons off protons are measured for photon energies from threshold to W=2400 MeV (T), 2280 MeV (E), 1620 MeV (P,H), or 1820 MeV (G), covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, JüBo, and BnGa partial-wave analyses. A refit within the BnGa approach including further data yields precise branching ratios for the Nη decay of nucleon resonances. A Nη-branching ratio of 0.33±0.04 for N(1650)1/2− is found, which reduces the large and controversially discussed Nη-branching ratio difference of the two lowest mass JP=1/2−-resonances significantly. Keywords: Baryon spectroscopy, Meson photoproduction, Polarization observables
Published: 2020
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25. K− over K+ multiplicity ratio for kaons produced in DIS with a large fraction of the virtual-photon energy

Author: R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, G. Pesaro, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, H. Schmieden, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, F. Sozzi, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, A. Vidon, M. Virius, S. Wallner, M. Wilfert, R. Windmolders, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, and M. Ziembicki
Subjects: Physics, QC1-999
Abstract: The K− over K+ multiplicity ratio is measured in deep-inelastic scattering, for the first time for kaons carrying a large fraction z of the virtual-photon energy. The data were obtained by the COMPASS collaboration using a 160 GeV muon beam and an isoscalar 6LiD target. The regime of deep-inelastic scattering is ensured by requiring Q2>1(GeV/c)2 for the photon virtuality and W>5GeV/c2 for the invariant mass of the produced hadronic system. Kaons are identified in the momentum range from 12 GeV/c to 40 GeV/c, thereby restricting the range in Bjorken-x to 0.010.75. For very large values of z, i.e. z>0.8, we observe the kaon multiplicity ratio to fall below the lower limits expected from calculations based on leading and next-to-leading order perturbative quantum chromodynamics. Also, the kaon multiplicity ratio shows a strong dependence on the missing mass of the single-kaon production process. This suggests that within the perturbative quantum chromodynamics formalism an additional correction may be required, which takes into account the phase space available for hadronisation.
Published: 2018
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26. Azimuthal asymmetries of charged hadrons produced in high-energy muon scattering off longitudinally polarised deuterons

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M. G. Alexeev, G. D. Alexeev, A. Amoroso, V. Andrieux, N. V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C. D. R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E. R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M. L. Crespo, Q. Curiel, S. Dalla Torre, S. S. Dasgupta, S. Dasgupta, O. Yu. Denisov, L. Dhara, S. V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P. D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger jr., H. Fischer, C. Franco, N. du Fresne von Vijayan Hohenesche, J. M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F. H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d’Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G. V. Khaustov, Yu. A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J. H. Koivuniemi, V. N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V. F. Konstantinov, A. M. Kotzinian, O. M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z. V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R. P. Kurjata, A. A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G. K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G. V. Meshcheryakov, M. Meyer, W. Meyer, Yu. V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A. S. Nunes, A. G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D. V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V. A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N. S. Rossiyskaya, D. I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V. D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I. A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink
Subjects: Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Abstract Single hadron azimuthal asymmetries of positive and negative hadrons produced in muon semi-inclusive deep inelastic scattering off longitudinally polarised deuterons are determined using the 2006 COMPASS data and also combined all deuteron COMPASS data. For each hadron charge, the dependence of the azimuthal asymmetry on the hadron azimuthal angle $$\phi $$ ϕ is obtained by means of a five-parameter fitting function that besides a $$\phi $$ ϕ -independent term includes four modulations predicted by theory: $$\sin \phi $$ sinϕ , $$\sin 2 \phi $$ sin2ϕ , $$\sin 3\phi $$ sin3ϕ and $$\cos \phi $$ cosϕ . The amplitudes of the five terms have been extracted, first, for the hadrons in the whole available kinematic region. In further fits, performed for hadrons from a restricted kinematic region, the $$\phi $$ ϕ -dependence is determined as a function of one of three variables (Bjorken-x, fractional energy of virtual photon taken by the outgoing hadron and hadron transverse momentum), while disregarding the others. Except the $$\phi $$ ϕ -independent term, all the modulation amplitudes are very small, and no clear kinematic dependence could be observed within experimental uncertainties.
Published: 2018
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27. Testing the consistency between changes in simulated climate and Alpine glacier length over the past millennium

Author: H. Goosse, P.-Y. Barriat, Q. Dalaiden, F. Klein, B. Marzeion, F. Maussion, P. Pelucchi, and A. Vlug
Subjects: Environmental pollution, TD172-193.5, Environmental protection, TD169-171.8, Environmental sciences, GE1-350
Abstract: It is standard to compare climate model results covering the past millennium and reconstructions based on various archives in order to test the ability of models to reproduce the observed climate variability. Up to now, glacier length fluctuations have not been used systematically in this framework even though they offer information on multi-decadal to centennial variations complementary to other records. One reason is that glacier length depends on several complex factors and so cannot be directly linked to the simulated climate. However, climate model skill can be measured by comparing the glacier length computed by a glacier model driven by simulated temperature and precipitation to observed glacier length variations. This is done here using the version 1.0 of the Open Global Glacier Model (OGGM) forced by fields derived from a range of simulations performed with global climate models over the past millennium. The glacier model is applied to a set of Alpine glaciers for which observations cover at least the 20th century. The observed glacier length fluctuations are generally well within the range of the simulations driven by the various climate model results, showing a general consistency with this ensemble of simulations. Sensitivity experiments indicate that the results are much more sensitive to the simulated climate than to OGGM parameters. This confirms that the simulations of glacier length can be used to evaluate the climate model performance, in particular the simulated summer temperatures that largely control the glacier changes in our region of interest. Simulated glacier length is strongly influenced by the internal variability in the system, putting limitations on the model–data comparison for some variables like the trends over the 20th century in the Alps. Nevertheless, comparison of glacier length fluctuations on longer timescales, for instance between the 18th century and the late 20th century, appear less influenced by the natural variability and indicate clear differences in the behaviour of the various climate models.
Published: 2018
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28. Gas-phase composition and secondary organic aerosol formation from standard and particle filter-retrofitted gasoline direct injection vehicles investigated in a batch and flow reactor

Author: S. M. Pieber, N. K. Kumar, F. Klein, P. Comte, D. Bhattu, J. Dommen, E. A. Bruns, D. Kılıç, I. El Haddad, A. Keller, J. Czerwinski, N. Heeb, U. Baltensperger, J. G. Slowik, and A. S. H. Prévôt
Subjects: Physics, QC1-999, Chemistry, QD1-999
Abstract: Gasoline direct injection (GDI) vehicles have recently been identified as a significant source of carbonaceous aerosol, of both primary and secondary origin. Here we investigated primary emissions and secondary organic aerosol (SOA) from four GDI vehicles, two of which were also retrofitted with a prototype gasoline particulate filter (GPF). We studied two driving test cycles under cold- and hot-engine conditions. Emissions were characterized by proton transfer reaction time-of-flight mass spectrometry (gaseous non-methane organic compounds, NMOCs), aerosol mass spectrometry (sub-micron non-refractory particles) and light attenuation measurements (equivalent black carbon (eBC) determination using Aethalometers) together with supporting instrumentation. Atmospheric processing was simulated using the PSI mobile smog chamber (SC) and the potential aerosol mass oxidation flow reactor (OFR). Overall, primary and secondary particulate matter (PM) and NMOC emissions were dominated by the engine cold start, i.e., before thermal activation of the catalytic after-treatment system. Trends in the SOA oxygen to carbon ratio (O : C) for OFR and SC were related to different OH exposures, but divergences in the H : C remained unexplained. SOA yields agreed within experimental variability between the two systems, with a tendency for higher values in the OFR than in the SC (or, vice versa, lower values in the SC). A few aromatic compounds dominated the NMOC emissions, primarily benzene, toluene, xylene isomers/ethylbenzene and C3-benzene. A significant fraction of the SOA was explained by those compounds, based on comparison of effective SOA yield curves with those of toluene, o-xylene and 1,2,4-trimethylbenzene determined in our OFR, as well as others from literature. Remaining discrepancies, which were smaller in the SC and larger in the OFR, were up to a factor of 2 and may have resulted from diverse reasons including unaccounted precursors and matrix effects. GPF retrofitting significantly reduced primary PM through removal of refractory eBC and partially removed the minor POA fraction. At cold-started conditions it did not affect hydrocarbon emission factors, relative chemical composition of NMOCs or SOA formation, and likewise SOA yields and bulk composition remained unaffected. GPF-induced effects at hot-engine conditions deserve attention in further studies.
Published: 2018
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29. Longitudinal double-spin asymmetry A1p and spin-dependent structure function g1p of the proton at small values of x and Q2

Author: M. Aghasyan, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, J. Veloso, A. Vidon, M. Virius, S. Wallner, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, and M. Ziembicki
Subjects: Physics, QC1-999
Abstract: We present a precise measurement of the proton longitudinal double-spin asymmetry A1p and the proton spin-dependent structure function g1p at photon virtualities 0.006(GeV/c)2
Published: 2018
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30. Oxidation resistance of bulk plasma-facing tungsten alloys

Author: F. Klein, T. Wegener, A. Litnovsky, M. Rasinski, X.Y. Tan, J. Gonzalez-Julian, J. Schmitz, M. Bram, J.W. Coenen, and Ch. Linsmeier
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: Tungsten (W) currently is the main candidate as plasma-facing armour material for the first wall of future fusion reactors, like DEMO. Advantages of W include a high melting point, high thermal conductivity, low tritium retention, and low erosion yield. However, in case of an accident, air ingress into the vacuum vessel can occur and the temperature of the first wall can reach 1200 K to 1450 K due to nuclear decay heat. In the absence of cooling, the temperature will remain in that range for several weeks. At these temperatures the radioactive tungsten oxide volatilizes. Therefore, ‘smart’ W alloys are developed that aim to preserve the properties of W during plasma operation coupled with suppressed tungsten oxide formation in case of an accident.This study focusses on oxidation studies at 1273 K of samples produced by mechanical alloying followed by field assisted sintering. In a first step the sintering is optimized for tungsten (W) – chromium (Cr) -yttrium (Y) alloys. It is shown that the best oxidation resistance is achieved with submicron grain sizes. This yields a closed, protective oxide layer. In a second step the influence of the grinding process during sample preparation is analysed. It is shown that scratches initiate failure of the protective oxide. In a third step the oxidation and sublimation is measured for weeks – for the first time the sublimation is directly measured in order to determine the potential hazard in comparison to pure W. It is shown that the oxidation is suppressed in comparison to pure W. However, sublimation at a rate of 1×10−6mgcm−2s−1 starts after a few days. Nevertheless, the progess in smart alloys is evident: sublimation is delayed by about two days and complete mechanical destruction of the first wall is avoided. Keywords: W-based alloys, W–Cr–Y alloys, Oxidation resistance, DEMO
Published: 2018
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31. WCrY smart alloys as advanced plasma-facing materials – Exposure to steady-state pure deuterium plasmas in PSI-2

Author: J. Schmitz, A. Litnovsky, F. Klein, T. Wegener, X.Y. Tan, M. Rasinski, A. Mutzke, P. Hansen, A. Kreter, A. Pospieszczyk, S. Möller, J.W. Coenen, Ch. Linsmeier, U. Breuer, J. Gonzalez-Julian, and M. Bram
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: In this paper the impact of steady state pure D plasma on WCrY smart alloys at ion energies of 120 and 220 eV is reported. For this purpose a comparison with simultaneously exposed pure W samples is drawn. Different analysis techniques employed for pre- and post-plasma sample analysis hint at a significant depletion of Cr and enrichment of W for lower ion energies. Preferential sputtering leads to enhanced volumetric loss at 220 eV. Analysis of redeposited material indicated local redeposition of Cr. Modelling the ion irradiation with SDTrimSP is used to further interpret experimental results. Depending on the sample temperature during plasma exposure and the magnitude of the ion flux, diffusion of Cr towards the surface is a determining factor for erosion of smart alloys for higher ion energies. Keywords: Smart alloys, Plasma-wall-interaction, Plasma ion irradiation, DEMO, W-based alloys
Published: 2018
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32. Identification of secondary aerosol precursors emitted by an aircraft turbofan

Author: D. Kılıç, I. El Haddad, B. T. Brem, E. Bruns, C. Bozetti, J. Corbin, L. Durdina, R.-J. Huang, J. Jiang, F. Klein, A. Lavi, S. M. Pieber, T. Rindlisbacher, Y. Rudich, J. G. Slowik, J. Wang, U. Baltensperger, and A. S. H. Prévôt
Subjects: Physics, QC1-999, Chemistry, QD1-999
Abstract: Oxidative processing of aircraft turbine-engine exhausts was studied using a potential aerosol mass (PAM) chamber at different engine loads corresponding to typical flight operations. Measurements were conducted at an engine test cell. Organic gases (OGs) and particle emissions pre- and post-PAM were measured. A suite of instruments, including a proton-transfer-reaction mass spectrometer (PTR-MS) for OGs, a multigas analyzer for CO, CO2, NOx, and an aerosol mass spectrometer (AMS) for nonrefractory particulate matter (NR-PM1) were used. Total aerosol mass was dominated by secondary aerosol formation, which was approximately 2 orders of magnitude higher than the primary aerosol. The chemical composition of both gaseous and particle emissions were also monitored at different engine loads and were thrust-dependent. At idling load (thrust 2.5–7 %), more than 90 % of the secondary particle mass was organic and could mostly be explained by the oxidation of gaseous aromatic species, e.g., benzene; toluene; xylenes; tri-, tetra-, and pentamethyl-benzene; and naphthalene. The oxygenated-aromatics, e.g., phenol, furans, were also included in this aromatic fraction and their oxidation could alone explain up to 25 % of the secondary organic particle mass at idling loads. The organic fraction decreased with thrust level, while the inorganic fraction increased. At an approximated cruise load sulfates comprised 85 % of the total secondary particle mass.
Published: 2018
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33. New analysis of ηπ tensor resonances measured at the COMPASS experiment

Author: A. Jackura, C. Fernández-Ramírez, M. Mikhasenko, A. Pilloni, V. Mathieu, J. Nys, V. Pauk, A.P. Szczepaniak, G. Fox, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, T. Schlüter, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, J. Veloso, A. Vidon, M. Virius, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, and M. Ziembicki
Subjects: Physics, QC1-999
Abstract: We present a new amplitude analysis of the ηπ D-wave in the reaction π−p→ηπ−p measured by COMPASS. Employing an analytical model based on the principles of the relativistic S-matrix, we find two resonances that can be identified with the a2(1320) and the excited a2′(1700), and perform a comprehensive analysis of their pole positions. For the mass and width of the a2 we find M=(1307±1±6) MeV and Γ=(112±1±8) MeV, and for the excited state a2′ we obtain M=(1720±10±60) MeV and Γ=(280±10±70) MeV, respectively.
Published: 2018
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34. Formation of highly oxygenated organic molecules from aromatic compounds

Author: U. Molteni, F. Bianchi, F. Klein, I. El Haddad, C. Frege, M. J. Rossi, J. Dommen, and U. Baltensperger
Subjects: Physics, QC1-999, Chemistry, QD1-999
Abstract: Anthropogenic volatile organic compounds (AVOCs) often dominate the urban atmosphere and consist to a large degree of aromatic hydrocarbons (ArHCs), such as benzene, toluene, xylenes, and trimethylbenzenes, e.g., from the handling and combustion of fuels. These compounds are important precursors for the formation of secondary organic aerosol. Here we show that the oxidation of aromatics with OH leads to a subsequent autoxidation chain reaction forming highly oxygenated molecules (HOMs) with an O : C ratio of up to 1.09. This is exemplified for five single-ring ArHCs (benzene, toluene, o-/m-/p-xylene, mesitylene (1,3,5-trimethylbenzene) and ethylbenzene), as well as two conjugated polycyclic ArHCs (naphthalene and biphenyl). We report the elemental composition of the HOMs and show the differences in the oxidation patterns of these ArHCs. A potential pathway for the formation of these HOMs from aromatics is presented and discussed. We hypothesize that AVOCs may contribute substantially to new particle formation events that have been detected in urban areas.
Published: 2018
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35. Hydroclimate variability in Scandinavia over the last millennium – insights from a climate model–proxy data comparison

Author: K. Seftigen, H. Goosse, F. Klein, and D. Chen
Subjects: Environmental pollution, TD172-193.5, Environmental protection, TD169-171.8, Environmental sciences, GE1-350
Abstract: The integration of climate proxy information with general circulation model (GCM) results offers considerable potential for deriving greater understanding of the mechanisms underlying climate variability, as well as unique opportunities for out-of-sample evaluations of model performance. In this study, we combine insights from a new tree-ring hydroclimate reconstruction from Scandinavia with projections from a suite of forced transient simulations of the last millennium and historical intervals from the CMIP5 and PMIP3 archives. Model simulations and proxy reconstruction data are found to broadly agree on the modes of atmospheric variability that produce droughts–pluvials in the region. Despite these dynamical similarities, large differences between simulated and reconstructed hydroclimate time series remain. We find that the GCM-simulated multi-decadal and/or longer hydroclimate variability is systematically smaller than the proxy-based estimates, whereas the dominance of GCM-simulated high-frequency components of variability is not reflected in the proxy record. Furthermore, the paleoclimate evidence indicates in-phase coherencies between regional hydroclimate and temperature on decadal timescales, i.e., sustained wet periods have often been concurrent with warm periods and vice versa. The CMIP5–PMIP3 archive suggests, however, out-of-phase coherencies between the two variables in the last millennium. The lack of adequate understanding of mechanisms linking temperature and moisture supply on longer timescales has serious implications for attribution and prediction of regional hydroclimate changes. Our findings stress the need for further paleoclimate data–model intercomparison efforts to expand our understanding of the dynamics of hydroclimate variability and change, to enhance our ability to evaluate climate models, and to provide a more comprehensive view of future drought and pluvial risks.
Published: 2017
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36. First measurement of the Sivers asymmetry for gluons using SIDIS data

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, A. Vauth, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink
Subjects: Deep inelastic scattering, Gluon, Sivers, TMD, PDF, Physics, QC1-999
Abstract: The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. For quarks, it was studied in previous measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it was found to be non-zero. In this letter the evaluation of the Sivers asymmetry for gluons is presented. The contribution of the photon–gluon fusion subprocess is enhanced by requiring two high transverse-momentum hadrons. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon–gluon fusion, QCD Compton scattering and the leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simultaneously extracted using the LEPTO event generator and a neural network approach. The method is applied to samples of events containing at least two hadrons with large transverse momentum from the COMPASS data taken with a 160 GeV/c muon beam scattered off transversely polarised deuterons and protons. With a significance of about two standard deviations, a negative value is obtained for the gluon Sivers asymmetry. The result of a similar analysis for a Collins-like asymmetry for gluons is consistent with zero.
Published: 2017
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37. Smart alloys for a future fusion power plant: First studies under stationary plasma load and in accidental conditions

Author: A. Litnovsky, T. Wegener, F. Klein, Ch. Linsmeier, M. Rasinski, A. Kreter, B. Unterberg, M. Vogel, S. Kraus, U. Breuer, C. Garcia-Rosales, A. Calvo, and N. Ordas
Subjects: Nuclear engineering. Atomic power, TK9001-9401
Abstract: In case of an accident in the future fusion power plant like DEMO, the loss-of-coolant may happen simultaneously with air ingress into the vacuum vessel. The radioactive tungsten and its isotopes from the first wall may become oxidized and vaporized into the environment. The so-called “smart” alloys are under development to suppress the mobilization of oxidized tungsten. Smart alloys are aimed at adjusting their properties to environment. During regular operation, the preferential sputtering of alloying elements by plasma ions should leave almost pure tungsten surface facing the plasma. Under accidental conditions, the alloying elements in the bulk will form an oxide layer protecting tungsten from mobilization.The first direct comparative test of pure tungsten and smart alloys under identical plasma conditions was performed. Tungsten–chromium–titanium alloys were exposed simultaneously with tungsten samples to stationary deuterium plasma in linear plasma device PSI-2. The ion energy and the temperature of samples corresponded well the conditions at the first wall in DEMO. The accumulated fluence was 1.3 × 1026 ion/m2. The weight loss of pure tungsten samples after exposure was ΔmW = 1000–1150µg. The measured weight loss of sputtered smart alloy sample ΔmSA = 1240µg corresponds very well to that of pure tungsten providing experimental evidence of good resistance of smart alloys to plasma sputtering.Plasma exposure was followed by the oxidation of alloys at 1000°C accomplishing the first test of these new materials both in a plasma environment and under accidental conditions. Compared to pure tungsten, smart alloys featured the 3-fold suppression of oxidation. Plasma exposure did not affect the oxidation resistance of smart alloys. At the same time, the self-passivation of the protective layer did not occur, calling for further optimization of alloys. Keywords: DEMO, Advanced plasma-facing materials, Smart tungsten alloys, Suppressed oxidation, Plasma sputtering, Accidental conditions
Published: 2017
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38. Sivers asymmetry extracted in SIDIS at the hard scales of the Drell–Yan process at COMPASS

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink
Subjects: SIDIS, Drell–Yan, Spin, Azimuthal asymmetries, Sivers, TMDs, Physics, QC1-999
Abstract: Eight proton transverse-spin-dependent azimuthal asymmetries are extracted in four regions of the photon virtuality Q2 from the COMPASS 2010 semi-inclusive hadron measurements in deep inelastic muon–nucleon scattering. These Q2 regions correspond to the four regions of the di-muon mass Q2 used in the ongoing analyses of the COMPASS Drell–Yan measurements, which allows for a future direct comparison of the nucleon transverse-momentum-dependent parton distribution functions extracted from these two alternative measurements. In addition, for the azimuthal asymmetries induced by the Sivers transverse-momentum-dependent parton distribution function various two-dimensional kinematic dependences are presented. The integrated Sivers asymmetries are found to be positive with an accuracy that appears to be sufficient to test the sign change of the Sivers function predicted by Quantum Chromodynamics.
Published: 2017
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39. Final COMPASS results on the deuteron spin-dependent structure function g1d and the Bjorken sum rule

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, A. Vauth, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink
Subjects: COMPASS, Deep inelastic scattering, Spin, Structure function, Parton helicity distributions, Physics, QC1-999
Abstract: Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV/c)24GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2. Towards lowest accessible values of x, g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c)2)=0.32±0.02stat±0.04syst±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.
Published: 2017
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40. Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink
Subjects: Deep inelastic scattering, Kaon multiplicities, Quark fragmentation functions, Strange quark, Physics, QC1-999
Abstract: Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6LiD target. They cover the kinematic domain 1(GeV/c)25 GeV/c2 in the invariant mass of the hadronic system. The results from the sum of the z-integrated K+ and K− multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.
Published: 2017
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41. Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M. G. Alexeev, G. D. Alexeev, A. Amoroso, V. Andrieux, N. V. Anfimov, V. Anosov, W. Augustyniak, A. Austregesilo, C. D. R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E. R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M. L. Crespo, Q. Curiel, S. Dalla Torre, S. S. Dasgupta, S. Dasgupta, O. Yu. Denisov, L. Dhara, S. V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P. D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J. M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F. H. Heinsius, R. Heitz, F. Herrmann, F. Hinterberger, N. Horikawa, N. d’Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G. V. Khaustov, Yu. A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J. H. Koivuniemi, V. N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V. F. Konstantinov, A. M. Kotzinian, O. M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z. V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R. P. Kurjata, A. A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G. K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G. V. Meshcheryakov, W. Meyer, T. Michigami, Yu. V. Mikhailov, M. Mikhasenko, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V. I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A. S. Nunes, A. G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D. V. Peshekhonov, S. Platchkov, J. Pochodzalla, V. A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N. S. Rossiyskaya, D. I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V. D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I. A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, E. Seder, A. Selyunin, O. Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, A. Zink, and COMPASS Collaboration
Subjects: Transverse Momentum, Monte Carlo, Systematic Uncertainty, Parton Shower, Monte Carlo Model, Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Abstract Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality $$Q^2>1~(\mathrm{GeV}/c)^2$$ Q 2 > 1 ( GeV / c ) 2 . The data were obtained by the COMPASS experiment at CERN using a 160 GeV/c polarised muon beam impinging on a polarised $$^6$$ 6 LiD target. By analysing the full range in hadron transverse momentum $$p_\mathrm{T}$$ p T , the different $$p_\mathrm{T}$$ p T -dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation $$\Delta g/g$$ Δ g / g is evaluated at leading order in pQCD at a hard scale of $$\mu ^2= \langle Q^2 \rangle = 3 (\mathrm{GeV}/c)^2$$ μ 2 = ⟨ Q 2 ⟩ = 3 ( GeV / c ) 2 . It is determined in three intervals of the nucleon momentum fraction carried by gluons, $$x_\mathrm{g}$$ x g , covering the range $$0.04 \!
Published: 2017
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42. Exclusive ω meson muoproduction on transversely polarised protons

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, R. Heitz, F. Herrmann, F. Hinterberger, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, T. Michigami, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, E. Seder, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, D. Steffen, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink
Subjects: Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Exclusive production of ω mesons was studied at the COMPASS experiment by scattering 160 GeV/c muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured in the range of photon virtuality 1 (GeV/c)2
Published: 2017
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43. Multiplicities of charged pions and charged hadrons from deep-inelastic scattering of muons off an isoscalar target

Author: C. Adolph, M. Aghasyan, R. Akhunzyanov, G.D. Alexeev, M.G. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, R. Heitz, F. Herrmann, F. Hinterberger, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, R. Kuhn, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, T. Michigami, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, E. Seder, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, D. Steffen, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink
Subjects: Deep inelastic scattering, Pion multiplicities, Fragmentation functions, Physics, QC1-999
Abstract: Multiplicities of charged pions and charged hadrons produced in deep-inelastic scattering were measured in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y and the relative hadron energy z. Data were obtained by the COMPASS Collaboration using a 160GeV muon beam and an isoscalar target (6LiD). They cover the kinematic domain in the photon virtuality Q2>1(GeV/c)2, 0.004
Published: 2017
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44. Characterization of gas-phase organics using proton transfer reaction time-of-flight mass spectrometry: fresh and aged residential wood combustion emissions

Author: E. A. Bruns, J. G. Slowik, I. El Haddad, D. Kilic, F. Klein, J. Dommen, B. Temime-Roussel, N. Marchand, U. Baltensperger, and A. S. H. Prévôt
Subjects: Physics, QC1-999, Chemistry, QD1-999
Abstract: Organic gases emitted during the flaming phase of residential wood combustion are characterized individually and by functionality using proton transfer reaction time-of-flight mass spectrometry. The evolution of the organic gases is monitored during photochemical aging. Primary gaseous emissions are dominated by oxygenated species (e.g., acetic acid, acetaldehyde, phenol and methanol), many of which have deleterious health effects and play an important role in atmospheric processes such as secondary organic aerosol formation and ozone production. Residential wood combustion emissions differ considerably from open biomass burning in both absolute magnitude and relative composition. Ratios of acetonitrile, a potential biomass burning marker, to CO are considerably lower ( ∼ 0.09 pptv ppbv−1) than those observed in air masses influenced by open burning ( ∼ 1–2 pptv ppbv−1), which may make differentiation from background levels difficult, even in regions heavily impacted by residential wood burning. A considerable amount of formic acid forms during aging ( ∼ 200–600 mg kg−1 at an OH exposure of (4.5–5.5) × 107 molec cm−3 h), indicating residential wood combustion can be an important local source for this acid, the quantities of which are currently underestimated in models. Phthalic anhydride, a naphthalene oxidation product, is also formed in considerable quantities with aging ( ∼ 55–75 mg kg−1 at an OH exposure of (4.5–5.5) × 107 molec cm−3 h). Although total NMOG emissions vary by up to a factor of ∼ 9 between burns, SOA formation potential does not scale with total NMOG emissions and is similar in all experiments. This study is the first thorough characterization of both primary and aged organic gases from residential wood combustion and provides a benchmark for comparison of emissions generated under different burn parameters.
Published: 2017
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45. Development of yttrium-containing self-passivating tungsten alloys for future fusion power plants

Author: T. Wegener, F. Klein, A. Litnovsky, M. Rasinski, J. Brinkmann, F. Koch, and Ch. Linsmeier
Subjects: W-based alloys, W-Cr-Y alloys, Oxide resistant W-Cr-Y alloys, Nuclear engineering. Atomic power, TK9001-9401
Abstract: Tungsten is a prime material candidate for the first wall of a future fusion reactor. In the case of a loss-of-coolant accident (LOCA) wall temperatures of about 1450 K could be reached lasting about 30–60 days due to nuclear decay heat. In the worst case scenario combining LOCA with air ingress, the formation and release of highly volatile and radioactive tungsten trioxide (WO3) into the environment can occur. Smart self-passivating tungsten alloys preventing the formation of WO3 can be a way to mitigate this release. In this contribution we present the studies of a new yttrium-containing W-Cr-Y alloys. The extent up to which yttrium acts as an active element improving the adherence and stability of the protective Cr2O3 layer formed during oxidation is assessed. The approach is similar to the one taken for high-temperature steels where active elements stabilize the oxide layers at a substantially reduced thickness by changing the oxygen diffusion and improving the adherence of the protective oxide layer by e.g. avoiding of pores. Further, simulations on mobilized material for the case of a LOCA are developed. In addition, the loss of alloying elements during normal operation of a reactor is estimated. This is done by modelling a thermally activated diffusion, using a diffusion coefficient which is extrapolated from experimental data at higher values. The oxidation behaviour of magnetron sputtered and therefore alloyed at the atomic level W-Cr-Y alloys is tested in a thermo-gravimetric facility. The isothermal oxidations are performed in a gas mixture, containing 20 kPa oxygen and 80 kPa argon under ambient pressure at temperatures of 1273 K and 1473 K, respectively. Experiments with W-Cr-Y show a parabolic oxidation rate of kp=3·10−6mg2cm−4s−1 which is more than five orders of magnitude lower than that of pure tungsten at 1273 K. Investigations using X-ray diffraction analysis and focused ion beam cross-sections in combination with scanning electron microscopy and energy dispersive X-ray spectroscopy are conducted. A protective Cr2O3 layer is detected on the surface with a thickness between 100 and 300 nm.
Published: 2016
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46. High precision measurement of Compton scattering in the 5 GeV region

Author: P. Ambrozewicz, L. Ye, Y. Prok, I. Larin, A. Ahmidouch, K. Baker, V. Baturin, L. Benton, A. Bernstein, V. Burkert, E. Clinton, P.L. Cole, P. Collins, D. Dale, S. Danagoulian, G. Davidenko, R. Demirchyan, A. Deur, A. Dolgolenko, D. Dutta, G. Dzyubenko, A. Evdokimov, G. Fedotov, J. Feng, M. Gabrielyan, L. Gan, H. Gao, A. Gasparian, N. Gevorkyan, S. Gevorkyan, A. Glamazdin, V. Goryachev, L. Guo, V. Gyurjyan, K. Hardy, J. He, E. Isupov, M.M. Ito, L. Jiang, H. Kang, D. Kashy, M. Khandaker, P. Kingsberry, F. Klein, A. Kolarkar, M. Konchatnyi, O. Korchin, W. Korsch, O. Kosinov, S. Kowalski, M. Kubantsev, A. Kubarovsky, V. Kubarovsky, D. Lawrence, X. Li, M. Levillain, H. Lu, L. Ma, P. Martel, V. Matveev, D. McNulty, B. Mecking, A. Micherdzinska, B. Milbrath, R. Minehart, R. Miskimen, V. Mochalov, B. Morrison, S. Mtingwa, I. Nakagawa, S. Overby, E. Pasyuk, M. Payen, K. Park, R. Pedroni, W. Phelps, D. Protopopescu, D. Rimal, B.G. Ritchie, D. Romanov, C. Salgado, A. Shahinyan, A. Sitnikov, D. Sober, S. Stepanyan, W. Stephens, V. Tarasov, S. Taylor, A. Teymurazyan, J. Underwood, A. Vasiliev, V. Vishnyakov, D.P. Weygand, M. Wood, Y. Zhang, S. Zhou, and B. Zihlmann
Subjects: Physics, QC1-999
Abstract: The cross section of atomic electron Compton scattering γ+e→γ′+e′ was measured in the 4.400–5.475 GeV photon beam energy region by the PrimEx collaboration at Jefferson Lab with an accuracy of 2.6% and less. The results are consistent with theoretical predictions that include next-to-leading order radiative corrections. The measurements provide the first high precision test of this elementary QED process at beam energies greater than 0.1 GeV.
Published: 2019
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47. Comparison of simulated and reconstructed variations in East African hydroclimate over the last millennium

Author: F. Klein, H. Goosse, N. E. Graham, and D. Verschuren
Subjects: Environmental pollution, TD172-193.5, Environmental protection, TD169-171.8, Environmental sciences, GE1-350
Abstract: The multi-decadal to centennial hydroclimate changes in East Africa over the last millennium are studied by comparing the results of forced transient simulations by six general circulation models (GCMs) with published hydroclimate reconstructions from four lakes: Challa and Naivasha in equatorial East Africa, and Masoko and Malawi in southeastern inter-tropical Africa. All GCMs simulate fairly well the unimodal seasonal cycle of precipitation in the Masoko–Malawi region, while the bimodal seasonal cycle characterizing the Challa–Naivasha region is generally less well captured by most models. Model results and lake-based hydroclimate reconstructions display very different temporal patterns over the last millennium. Additionally, there is no common signal among the model time series, at least until 1850. This suggests that simulated hydroclimate fluctuations are mostly driven by internal variability rather than by common external forcing. After 1850, half of the models simulate a relatively clear response to forcing, but this response is different between the models. Overall, the link between precipitation and tropical sea surface temperatures (SSTs) over the pre-industrial portion of the last millennium is stronger and more robust for the Challa–Naivasha region than for the Masoko–Malawi region. At the inter-annual timescale, last-millennium Challa–Naivasha precipitation is positively (negatively) correlated with western (eastern) Indian Ocean SST, while the influence of the Pacific Ocean appears weak and unclear. Although most often not significant, the same pattern of correlations between East African rainfall and the Indian Ocean SST is still visible when using the last-millennium time series smoothed to highlight centennial variability, but only in fixed-forcing simulations. This means that, at the centennial timescale, the effect of (natural) climate forcing can mask the imprint of internal climate variability in large-scale teleconnections.
Published: 2016
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48. Interplay among transversity induced asymmetries in hadron leptoproduction

Author: C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, W.-C. Chang, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, N. d'Hose, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, A. Ferrero, M. Finger, M. Finger Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, N. Horikawa, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, G. Pesaro, M. Pesek, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, F. Sozzi, A. Srnka, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, T. Weisrock, M. Wilfert, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink
Subjects: Physics, QC1-999
Abstract: In the fragmentation of a transversely polarized quark several left–right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as the Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows quantitative relationships to be established among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.
Published: 2016
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49. The spin structure function g1p of the proton and a test of the Bjorken sum rule

Author: C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, C. Azevedo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, L. Capozza, W.-C. Chang, M. Chiosso, I. Choi, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, A. Ferrero, M. Finger, M. Finger jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse-Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, N. Horikawa, N. d'Hose, C. -Yu Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Novy, W.-D. Nowak, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pesek, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, E. Rocco, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, F. Sozzi, A. Srnka, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, T. Weisrock, M. Wilfert, R. Windmolders, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink
Subjects: Physics, QC1-999
Abstract: New results for the double spin asymmetry A1p and the proton longitudinal spin structure function g1p are presented. They were obtained by the COMPASS Collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH3 target. The data were collected in 2011 and complement those recorded in 2007 at 160 GeV, in particular at lower values of x. They improve the statistical precision of g1p(x) by about a factor of two in the region x≲0.02. A next-to-leading order QCD fit to the g1 world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, ΔΣ, ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of g1p. The uncertainty of ΔΣ is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function g1NS(x,Q2) yields as ratio of the axial and vector coupling constants |gA/gV|=1.22±0.05 (stat.)±0.10 (syst.), which validates the sum rule to an accuracy of about 9%.
Published: 2016
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50. Longitudinal double spin asymmetries in single hadron quasi-real photoproduction at high pT

Author: C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, W.-C. Chang, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, N. Kuchinski, R. Kuhn, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, F. Sozzi, A. Srnka, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink
Subjects: COMPASS, Deep inelastic scattering, Double spin asymmetry, High pT, ΔG, Physics, QC1-999
Abstract: We measured the longitudinal double spin asymmetries ALL for single hadron muoproduction off protons and deuterons at photon virtuality Q2
Published: 2016
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