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14 results on '"Lozza, Valentina"'

2. The SNO+ experiment: current status and future prospects

Author

Lozza, Valentina and SNO+ Collaboration

Abstract

Lozza, Valentina "The SNO+ experiment: current status and future prospects" in Proceedings, Magellan Workshop: Connecting Neutrino Physics and Astronomy / Dahmke, Stefan K.G., Meyer, Mikko, Vanhoefer, Laura (eds.), Deutsches Elektronen-Synchrotron, DESY : 2016 ; Magellan Workshop, 2016-03-17 - 2016-03-18, Hamburg Magellan Workshop, Hamburg, Germany, 17 Mar 2016 - 18 Mar 2016 ; DESY-PROC 87-94(2016). doi:10.3204/DESY-PROC-2016-05/5, SNO+ is a multi-purpose neutrino experiment whose main physics goal is the search for the neutrinoless double-beta ($0\nu\beta\beta$) decay of $^{130}$Te. With an initial loading of 0.5\% (by weight) of natural tellurium SNO+ is expected to reach a sensitivity on the $0\nu\beta\beta$ lifetime of the order of 10$^{26}$ years at 90\% C.L. in a 5-year run. Along with the $0\nu\beta\beta$ decay search, SNO+ has the capability to measure the low energy solar neutrinos, like pep and CNO neutrinos. It has also an extraordinary opportunity to do the first measurement of the supernova $\nu_x$ energy spectrum., Published by Deutsches Elektronen-Synchrotron, DESY, Hamburg

Published
2016
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3. CAST: Recent results & future outlook

Author

Papaevangelou, T., Aune, S., Barth, K., Belov, A., Borghi, S., Brauninger, H., Cantatore, Giovanni, Carmona, J. M., Cetin, S. A., Collar, J. I., Dafni, T., Davenport, M., Eleftheriadis, C., Elias, N., Ezer, C., Fanourakis, G., Ferrer Ribas, E., Fischer, H., Franz, J., Friedrich, P., Galan, J., Gardikiotis, A., Gazis, E. N., Geralis, T., Giomataris, I., Gninenko, S., Gomez, H., Gruber, E., Guthorl, T., Hartmann, R., Haug, F., Hasinoff, M., Hoffmann, D. H. H., Iguaz, J., Irastorza, I. G., Jacoby, J., Jakovcic, K., Kang, D., Karageorgopoulou, T., Karuza, M., Konigsmann, K., Kotthaus, R., Krcmar, M., Kousouris, K., Kuster, M., Lakic, B., Lang, P., Lasseur, C., Laurent, J. M., Liolios, A., Ljubicic, A., Lozza, Valentina, Lutz, G., Luzon, G., Miller, D. W., Mirizzi, A., Morales, J., Niinikoski, T., Nordt, A., Pivovaroff, M., Raiteri, G., Raffelt, G., Rashba, T., Riege, H., Rodriguez, A., Rosu, M., Ruz, J., Savvidis, I., Semertzidis, Y., Serpico, P., Silva, P. S., Solanki, S. K., Soufli, R., Stewart, L., Tomas, A., Tsagri, M., van Bibber, K., Vafeiadis, T., Villar, J., Vogel, J. K., Walckiers, L., Wong, Y., Yildiz, S. C., Zioutas, K., L. Baudis, M. Schumann, Papaevangelou, T., Aune, S., Barth, K., Belov, A., Borghi, S., Brauninger, H., Cantatore, Giovanni, Carmona, J. M., Cetin, S. A., Collar, J. I., Dafni, T., Davenport, M., Eleftheriadis, C., Elias, N., Ezer, C., Fanourakis, G., Ferrer Ribas, E., Fischer, H., Franz, J., Friedrich, P., Galan, J., Gardikiotis, A., Gazis, E. N., Geralis, T., Giomataris, I., Gninenko, S., Gomez, H., Gruber, E., Guthorl, T., Hartmann, R., Haug, F., Hasinoff, M., Hoffmann, D. H. H., Iguaz, J., Irastorza, I. G., Jacoby, J., Jakovcic, K., Kang, D., Karageorgopoulou, T., Karuza, M., Konigsmann, K., Kotthaus, R., Krcmar, M., Kousouris, K., Kuster, M., Lakic, B., Lang, P., Lasseur, C., Laurent, J. M., Liolios, A., Ljubicic, A., Lozza, Valentina, Lutz, G., Luzon, G., Miller, D. W., Mirizzi, A., Morales, J., Niinikoski, T., Nordt, A., Pivovaroff, M., Raiteri, G., Raffelt, G., Rashba, T., Riege, H., Rodriguez, A., Rosu, M., Ruz, J., Savvidis, I., Semertzidis, Y., Serpico, P., Silva, P. S., Solanki, S. K., Soufli, R., Stewart, L., Tomas, A., Tsagri, M., van Bibber, K., Vafeiadis, T., Villar, J., Vogel, J. K., Walckiers, L., Wong, Y., Yildiz, S. C., and Zioutas, K.

Subjects
axions, astroparticle physics, axion, solar physic, astroparticle physic, solar physics, dark matter
Abstract

The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipes of an LHC dipole. The analysis of data taken so far has shown no signal above the background, thus implying an upper limit to the axion-photon coupling of gaγ < 0.85 × 10−10GeV −1 at 95% CL for ma < 0.02 eV/c2. Ongoing measurements, with the magnet bores filled with a buffer gas (3He), are improving the sensitivity of the experiment for higher axion masses towards 1 eV/c2. Recent results, new ideas for Axion-Like Particle (WISPs) searches with CAST in the near future and the prospects of a new generation Helioscope are presented here.

Published
2010

4. Search for solar ALPS in the low energy range at CAST

Author

CANTATORE, GIOVANNI, LOZZA, VALENTINA, Karuza M., Jaeckel J., Lindner A., Redondo J., Cantatore, Giovanni, Karuza, M., and Lozza, Valentina

Subjects
Axion, WIMP, Axions, WIMPs, dark matter, low background detectors
Abstract

It has been shown that a detector system, sensitive to single photons in the eV range can be coupled to the CAST experiment [1]. However the detectors used had high background rates compared with the expected signal, thus a search for a detector suitable for integrating in the present setup and with a low background rates was initiated. A suitable detector candidate was found and results from first tests are presented.

Published
2010

5. 3He(alpha,gamma)7Be cross section at low energies

Author

G.Y. GYÜRKY, F. CONFORTOLA, H. COSTANTINI, A. FORMICOLA, D. BEMMERER, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z.S. FÜLÖP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. IMBRIANI, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, M. MARTA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, F. TERRASI, H. P. TRAUTVETTER, LOZZA, VALENTINA, Gyürky, G. Y., F., Confortola, H., Costantini, A., Formicola, D., Bemmerer, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fülöp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, Lozza, Valentina, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter

Subjects
Astrophysics (astro-ph), FOS: Physical sciences, Nuclear Experiment (nucl-ex), Astrophysics, Nuclear Experiment
Abstract

The flux of 7Be and 8B neutrinos from the Sun and the production of 7Li via primordial nucleosynthesis depend on the rate of the 3He(alpha,gamma)7Be reaction. In extension of a previous study showing cross section data at 127 - 167 keV center of mass energy, the present work reports on a measurement of the 3He(alpha,gamma)7Be cross section at 106 keV performed at Italy's Gran Sasso underground laboratory by the activation method. This energy is closer to the solar Gamow energy than ever reached before. The result is sigma = 0.567 +- 0.029(stat) +- 0.016(syst) nbarn. The data are compared with previous activation studies at high energy, and a recommended S(0) value for all 3He(alpha,gamma)7Be activation studies, including the present work, is given., Accepted for publication in PRC

Published
2007

6. Astrophysical S factor of the 3He(alpha,gamma)7Be reaction measured at low energy via detection of prompt and delayed gamma rays

Author

F. CONFORTOLA, D. BEMMERER, H. COSTANTINI, A. FORMICOLA, G.Y. GYÜRKY, P. BEZZON, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z.S. FÜLÖP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. IMBRIANI, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, M. MARTA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, F. TERRASI, H. P. TRAUTVETTER, LOZZA, VALENTINA, F., Confortola, D., Bemmerer, H., Costantini, A., Formicola, Gyürky, G. Y., P., Bezzon, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fülöp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, Lozza, Valentina, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter

Published
2007

9. Search for solar Axion Like Particles in the low energy range at CAST

Author

Giovanni Cantatore, G. Raiteri, Marin Karuza, V. Lozza, Cantatore, Giovanni, Karuza, Marin, Lozza, Valentina, and Raiteri, Giancarlo

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), solar axion, Photon, Physics::Instrumentation and Detectors, low background detectors, Flux, Elementary particle, Astrophysics, Avalanche photodiode, Physics::Geophysics, Computational physics, Massless particle, Particle decay, low background detector, solar axions, CAST, Instrumentation, Axion
Abstract

Axion Like Particles (ALPs) could be continuously produced in the Sun via the Primakoff process. The ALP flux could be seen on Earth by observing the photons produced by the ALP decay. The expected energy distribution of reconverted photons is peaked at 3 keV. There could be, however, a low energy tail due to various processes active in the Sun. We report results of the first test measurements in the low energy range performed at CAST along with a description of the experimental setup. Future detector developments are discussed and preliminary results on a liquid nitrogen cooled Avalanche Photodiode are presented.

Published
2010
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10. Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with (3)He Buffer Gas

Author

M, Arik, S, Aune, K, Barth, A, Belov, S, Borghi, H, Bräuninger, G, Cantatore, J M, Carmona, S A, Cetin, J I, Collar, T, Dafni, M, Davenport, C, Eleftheriadis, N, Elias, C, Ezer, G, Fanourakis, E, Ferrer-Ribas, P, Friedrich, J, Galán, J A, García, A, Gardikiotis, E N, Gazis, T, Geralis, I, Giomataris, S, Gninenko, H, Gómez, E, Gruber, T, Guthörl, R, Hartmann, F, Haug, M D, Hasinoff, D H H, Hoffmann, F J, Iguaz, I G, Irastorza, J, Jacoby, K, Jakovčić, M, Karuza, K, Königsmann, R, Kotthaus, M, Krčmar, M, Kuster, B, Lakić, J M, Laurent, A, Liolios, A, Ljubičić, V, Lozza, G, Lutz, G, Luzón, J, Morales, T, Niinikoski, A, Nordt, T, Papaevangelou, M J, Pivovaroff, G, Raffelt, T, Rashba, H, Riege, A, Rodríguez, M, Rosu, J, Ruz, I, Savvidis, P S, Silva, S K, Solanki, L, Stewart, A, Tomás, M, Tsagri, K, van Bibber, T, Vafeiadis, J A, Villar, J K, Vogel, S C, Yildiz, K, Zioutas, Arik, M., Aune, S., Barth, K., Belov, A., Borghi, S., Brauninger, H., Cantatore, Giovanni, Carmona, J. M., Cetin, S. A., Collar, J. I., Dafni, T., Davenport, M., Eleftheriadis, C., Elias, N., Ezer, C., Fanourakis, G., Ferrer Ribas, E., Friedrich, P., Galan, J., Garcia, J. A., Gardikiotis, A., Gazis, E. N., Geralis, T., Giomataris, I., Gninenko, S., Gomez, H., Gruber, E., Guthorl, T., Hartmann, R., Haug, F., Hasinoff, M. D., Hoffmann, D. H. H., Iguaz, F. J., Irastorza, I. G., Jacoby, J., Jakovcic, K., Karuza, M., Konigsmann, K., Kotthaus, R., Krcmar, M., Kuster, M., Lakic, B., Laurent, J. M., Liolios, A., Ljubicic, A., Lozza, Valentina, Lutz, G., Luzon, G., Morales, J., Niinikoski, T., Nordt, A., Papaevangelou, T., Pivovaroff, M. J., Raffelt, G., Rashba, T., Riege, H., Rodriguez, A., Rosu, M., Ruz, J., Savvidis, I., Silva, P. S., Solanki, S. K., Stewart, L., Tomas, A., Tsagri, M., van Bibber, K., Vafeiadis, T., Villar, J. A., Vogel, J. K., Yildiz, S. C., and Zioutas, K.

Subjects
solar axion, low background detectors, solar axions, photons, dark matter
Abstract

The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV≲m(a)≲0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(aγ)≲2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)≲1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

Published
2011

11. Latest results and prospects of the CERN Axion Solar Telescope

Author

I. Giomataris, C. Eleftheriadis, T. Guthörl, S. C. Yildiz, José Villar, A. Tomás, G Lutz, I. G. Irastorza, F.J. Iguaz, Georgios Fanourakis, Biljana Lakić, L. Stewart, Javier Galan, S. Aune, Hector Gomez, J. M. Carmona, Marin Karuza, Dieter H. H. Hoffmann, V. Lozza, Milica Krčmar, Ante Ljubičić, K. Königsmann, M. Davenport, Theodoros Vafeiadis, E. Gruber, J. M. Laurent, Joachim Jacoby, S. Borghi, F. Haug, Timur Rashba, T. Papaevangelou, M. Tsagri, M. D. Hasinoff, I. Savvidis, Heinrich Bräuninger, P. S. Silva, M. Rosu, Peter Friedrich, M. J. Pivovaroff, Serkant Ali Cetin, T. Geralis, Konstantin Zioutas, T. O. Niinikoski, Giovanni Cantatore, S. N. Gninenko, K. van Bibber, A. Gardikiotis, Raimo Hartmann, J. Ruz, A. Liolios, N. Elias, Sami K. Solanki, Markus Kuster, A Nordt, E. Ferrer-Ribas, Julia Vogel, K. Barth, G. Luzón, H. Riege, C. Ezer, T. Dafni, A Rodríguez, Krešimir Jakovčić, Evangelos Gazis, Georg G. Raffelt, Regina Soufli, A. Belov, J. Morales, Rainer Kotthaus, J. I. Collar, I. G., Irastorza, S., Aune, K., Barth, A., Belov, S., Borghi, H., Bräuninger, Cantatore, Giovanni, J. M., Carmona, S. A., Cetin, J. I., Collar, T., Dafni, M., Davenport, C., Eleftheriadi, N., Elia, C., Ezer, G., Fanouraki, E., Ferrer Riba, P., Friedrich, J., Galán, A., Gardikioti, E. N., Gazi, T., Gerali, I., Giomatari, S., Gninenko, H., Gómez, E., Gruber, T., Guthörl, R., Hartmann, F., Haug, M. D., Hasinoff, D. H. H., Hoffmann, F. J., Iguaz, J., Jacoby, K., Jakovčić, M., Karuza, K., Königsmann, R., Kotthau, M., Krčmar, M., Kuster, B., Lakić, J. M., Laurent, A., Liolio, A., Ljubičić, Lozza, Valentina, G., Lutz, G., Luzón, J., Morale, T., Niinikoski, A., Nordt, T., Papaevangelou, M. J., Pivovaroff, G., Raffelt, T., Rashba, H., Riege, A., Rodríguez, M., Rosu, J., Ruz, I., Savvidi, P. S., Silva, S. K., Solanki, R., Soufli, L., Stewart, A., Tomá, M., Tsagri, Bibber, K. v. a. n., T., Vafeiadi, J., Villar, J. K., Vogel, S. C., Yildiz, K., Zioutas, Doğuş Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, TR3959, Çetin, Serkant Ali, Ezer, C., and Yıldız, Süleyman Cenk

Subjects
History, Particle physics, axions, Physics::Instrumentation and Detectors, Dark matter, 01 natural sciences, 7. Clean energy, dark matter, Education, Phase I, 0103 physical sciences, 010306 general physics, CERN Axion Solar Telescopes, Axion, Primakoff effect, solar physics, Physics, High Magnetic Fields, Helioscope, Large Hadron Collider, 010308 nuclear & particles physics, Axion Dark Matter Experiment, solar physic, Solar physics, Computer Science Applications, ddc, axion, CERN Axion Solar Telescope
Abstract

Çetin, Serkant Ali (Dogus Author) -- Ezer, C. (Dogus Author) -- Yıldız, Süleyman Cenk (Dogus Author) The CERN Axion Solar Telescope (CAST) experiment searches for axions from the Sun converted into few keV photons via the inverse Primakoff effect in the high magnetic field of a superconducting Large Hadron Collider (LHC) decommissioned test magnet. After results obtained with vacuum in the magnet pipes (phase I of the experiment) as well as with 4He the collaboration is now immersed in the data taking with 3He, to be finished in 2011. The status of the experiment will be presented, including a preliminary exclusion plot of the first 3He data. CAST is currently sensitive to realistic QCD axion models at the sub-eV scale, and with axion-photon couplings down to the ∼ 2 × 10-10 GeV -1, compatible with solar life limits. Future plans include revisiting vaccuum and 4He configurations with improved sensitivity, as well as possible additional search for non-standard signals from chamaleons, paraphotons or other WISPs. For the longer term, we study the feasibility of an altogether improved version of the axion helioscope concept, with a jump in sensitivity of about one order of magnitude in gaγ beyond CAST.

Published
2011

12. Limits on Low Energy Photon-Photon Scattering from an Experiment on Magnetic Vacuum Birefringence

Author

S. Carusotto, Giuseppe Ruoso, E. Polacco, F. Della Valle, G. Di Domenico, Giovanni Cantatore, Marco Bregant, Marin Karuza, E. Zavattini, U. Gastaldi, Guido Zavattini, V. Lozza, Roberto Cimino, Edoardo Milotti, G. Raiteri, M., Bregant, Cantatore, Giovanni, S., Carusotto, R., Cimino, DELLA VALLE, Federico, G., DI DOMENICO, U., Gastaldi, Karuza, Marin, Lozza, Valentina, Milotti, Edoardo, E., Polacco, Raiteri, Giancarlo, G., Ruoso, E., Zavattini, and G., Zavattini

Subjects
Scattering cross-section, Nuclear and High Energy Physics, Photon, optical tests of Quantum Electrodynamics, FOS: Physical sciences, MAGNETIC BIREFRINGENCE of vacuum, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Low energy, diffusione, Quantum mechanics, Beam laser, Photon-photon scattering, Physics, Birefringence, Scattering, birifrangenza, scattering, interferometro Fabry-Perot, MAGNETIC BIREFRINGENCE, Atomic physics, Energy (signal processing), Photon scattering
Abstract

Experimental bounds on induced vacuum magnetic birefringence can be used to improve present photon-photon scattering limits in the electronvolt energy range. Measurements with the Polarizzazione del Vuoto con Laser apparatus [E. Zavattini et al., Phys. Rev. D 77, 032006 (2008)] at both $\ensuremath{\lambda}=1064$ and 532 nm lead to bounds on the parameter ${A}_{e}$, describing nonlinear effects in QED, of ${A}_{e}^{(1064)}l6.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21}\text{ }\text{ }{\mathrm{T}}^{\ensuremath{-}2}@1064\text{ }\text{ }\mathrm{nm}$ and ${A}_{e}^{(532)}l6.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21}\text{ }\text{ }{\mathrm{T}}^{\ensuremath{-}2}@532\text{ }\text{ }\mathrm{nm}$, respectively, at 95% confidence level, compared to the predicted value of ${A}_{e}=1.32\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}24}\text{ }\text{ }{\mathrm{T}}^{\ensuremath{-}2}$. The total photon-photon scattering cross section may also be expressed in terms of ${A}_{e}$, setting bounds for unpolarized light of ${\ensuremath{\sigma}}_{\ensuremath{\gamma}\ensuremath{\gamma}}^{(1064)}l4.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}62}\text{ }\text{ }{\mathrm{m}}^{2}$ and ${\ensuremath{\sigma}}_{\ensuremath{\gamma}\ensuremath{\gamma}}^{(532)}l2.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}60}\text{ }\text{ }{\mathrm{m}}^{2}$. Compared to the expected QED scattering cross section these results are a factor of $\ensuremath{\simeq}2\ifmmode\times\else\texttimes\fi{}{10}^{7}$ higher and represent an improvement of a factor about 500 on previous bounds based on ellipticity measurements and of a factor of about ${10}^{10}$ on bounds based on direct stimulated scattering measurements.

Published
2008

13. New PVLAS results and limits on magnetically induced optical rotation and ellipticity in vacuum

Author

E. Zavattini, Guido Zavattini, S. Carusotto, F. Della Valle, Roberto Cimino, V. Lozza, U. Gastaldi, E. Polacco, Marco Bregant, Giuseppe Ruoso, Giovanni Cantatore, Marin Karuza, G. Di Domenico, G. Raiteri, Edoardo Milotti, E., Zavattini, G., Zavattini, G., Ruoso, G., Raiteri, E., Polacco, Milotti, Edoardo, Lozza, Valentina, M., Karuza, U., Gastaldi, G., DI DOMENICO, DELLA VALLE, Federico, R., Cimino, S., Carusotto, Cantatore, Giovanni, and M., Bregant

Subjects
Physics, Test sperimentali dell'Elettrodinamica Quantistica, Nuclear and High Energy Physics, Angular momentum, Particle physics, PVLAS, Field (physics), Condensed matter physics, Scattering, Birifrangenza, Order (ring theory), FOS: Physical sciences, Ellissometria con interferometri Fabry-Perot, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Photon-photon scattering, Interferometro Fabry-Perot, Quantum field theory, Spin-½, Boson
Abstract

IIn 2006 the PVLAS collaboration reported the observation of an optical rotation generated in vacuum by a magnetic field. To further check against possible instrumental artifacts several upgrades to the PVLAS apparatus have been made during the last year. Two data taking runs, at the wavelength of 1064 nm, have been performed in the new configuration with magnetic field strengths of 2.3 T and 5 T. The 2.3 T field value was chosen in order to avoid stray fields. The new observations do not show the presence of a rotation signal down to the levels of $1.2\cdot 10^{-8}$ rad at 5 T and $1.0\cdot 10^{-8}$ rad at 2.3 T (at 95% c.l.) with 45000 passes in the magnetic field zone. In the same conditions no ellipticity signal was detected down to $1.4\cdot 10^{-8}$ at 2.3 T (at 95% c.l.), whereas at 5 T a signal is still present. The physical nature of this ellipticity as due to an effect depending on $B^2$ can be excluded by the measurement at 2.3 T. These new results completely exclude the previously published magnetically induced vacuum dichroism results, indicating that they were instrumental artifacts. These new results therefore also exclude the particle interpretation of the previous PVLAS results as due to a spin zero boson. The background ellipticity at 2.3 T can be used to determine a new limit on the total photon-photon scattering cross section of $\sigma_{\gamma\gamma} < 4.5 \cdot10^{-34}$ barn at 95% c.l.., Comment: 25 pages, 7 figures Main changes rel. to v.2: minor changes to abstract, replaced Figures 4,5,6, corrected typographical errors. Paper submitted to Physical Review D

Published
2008

14. Activation Measurement of the 3He(alpha,gamma)7Be Cross Section at Low Energy

Author

D. BEMMERER, F. CONFORTOLA, H. COSTANTINI, A. FORMICOLA, G. GYURKY, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z. FULOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, V. LOZZA, M. MARTA, R. MENEGAZZO, P. . PRATI, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, F. TERRASI, H. P. TRAUTVETTER, IMBRIANI, GIANLUCA, ROCA, VINCENZO, D., Bemmerer, F., Confortola, H., Costantini, A., Formicola, Gyürky, G. Y., R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fülöp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, Lozza, Valentina, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, H. P., Trautvetter, G., Gyurky, Z., Fulop, Imbriani, Gianluca, V., Lozza, Prati, P., and Roca, Vincenzo

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Nuclear Experiment (nucl-ex), Astrophysics, Nuclear Experiment
Abstract

The nuclear physics input from the 3He(alpha,gamma)7Be cross section is a major uncertainty in the fluxes of 7Be and 8B neutrinos from the Sun predicted by solar models and in the 7Li abundance obtained in big-bang nucleosynthesis calculations. The present work reports on a new precision experiment using the activation technique at energies directly relevant to big-bang nucleosynthesis. Previously such low energies had been reached experimentally only by the prompt-gamma technique and with inferior precision. Using a windowless gas target, high beam intensity, and low background gamma-counting facilities, the 3He(alpha,gamma)7Be cross section has been determined at 127, 148, and 169 keV center-of-mass energy with a total uncertainty of 4%. The sources of systematic uncertainty are discussed in detail. The present data can be used in big-bang nucleosynthesis calculations and to constrain the extrapolation of the 3He(alpha,gamma)7Be astrophysical S factor to solar energies.

Published
2006

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