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2,762 results on '"A. Lennarz"'

1. Degradation of thin carbon-backed lithium fluoride targets bombarded by 68 MeV 17O beams

Author

Y.H. Kim, B. Davids, M. Williams, K.H. Hudson, S. Upadhyayula, M. Alcorta, P. Machule, N.E. Esker, C.J. Griffin, J. Williams, D. Yates, A. Lennarz, C. Angus, G. Hackman, D.G. Kim, J. Son, J. Park, K. Pak, and Y.K. Kim

Subjects
Degradation, Lattice damage, Sputtering, Thermal evaporation, Target lifetime, LiF target, Nuclear engineering. Atomic power, TK9001-9401
Abstract

To analyze the cause of the destruction of thin, carbon-backed lithium fluoride targets during a measurement of the fusion of 7Li and 17O, we estimate theoretically the lifetimes of carbon and LiF films due to sputtering, thermal evaporation, and lattice damage and compare them with the lifetime observed in the experiment. Sputtering yields and thermal evaporation rates in carbon and LiF films are too low to play significant roles in the destruction of the targets. We estimate the lifetime of the target due to lattice damage of the carbon backing and the LiF film using a previously reported model. In the experiment, elastically scattered target and beam ions were detected by surface silicon barrier (SSB) detectors so that the product of the beam flux and the target density could be monitored during the experiment. The areas of the targets exposed to different beam intensities and fluences were degraded and then perforated, forming holes with a diameter around the beam spot size. Overall, the target thickness tends to decrease linearly as a function of the beam fluence. However, the thickness also exhibits an increasing interval after SSB counts per beam ion decreases linearly, extending the target lifetime. The lifetime of thin LiF film as determined by lattice damage is calculated for the first time using a lattice damage model, and the calculated lifetime agrees well with the observed target lifetime during the experiment. In experiments using a thin LiF target to induce nuclear reactions, this study suggests methods to predict the lifetime of the LiF film and arrange the experimental plan for maximum efficiency.

Published
2023
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2. Ion manipulation from liquid Xe to vacuum: Ba-tagging for a nEXO upgrade and future 0{\nu}\b{eta}\b{eta} experiments

Author

Ray, Dwaipayan, Collister, Robert, Rasiwala, Hussain, Backes, Lucas, Balbuena, Ali V., Brunner, Thomas, Casandjian, Iroise, Chambers, Chris, vitan, Megan, Daniels, Tim, Dilling, Jens, Elmansali, Ryan, Fairbank, William, Fudenberg, Daniel, Gornea, Razvan, Gratta, Giorgio, Iverson, Alec, Kwiatkowski, Anna A., Leach, Kyle G., Lennarz, Annika, Li, Zepeng, Medina-Peregrina, Melissa, Murray, Kevin, Sullivan, Kevin O, Ross, Regan, Shaikh, Raad, Shang, Xiao, Soderstrom, Joseph, Varentsov, Victor, and Yang, Liang

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

Neutrinoless double beta decay ($0 \nu \beta \beta$) provides a way to probe physics beyond the Standard Model of particle physics. The upcoming nEXO experiment will search for $0\nu\beta\beta$ decay in $^{136}$Xe with a projected half-life sensitivity exceeding $10^{28}$ years at the 90\% confidence level using a liquid xenon (LXe) Time Projection Chamber (TPC) filled with 5 tonnes of Xe enriched to $\sim$90\% in the $\beta \beta$-decaying isotope $^{136}$Xe. In parallel, a potential future upgrade to nEXO is being investigated with the aim to further suppress radioactive backgrounds, and to confirm $\beta \beta$-decay events. This technique, known as Ba-tagging, comprises of extracting and identifying the $\beta \beta$-decay daughter $^{136}$Ba ion. One tagging approach being pursued involves extracting a small volume of LXe in the vicinity of a potential $\beta \beta$-decay using a capillary tube and facilitating a liquid to gas phase transition by heating the capillary exit. The Ba ion is then separated from the accompanying Xe gas using a radio-frequency (RF) carpet and RF funnel, conclusively identifying the ion as $^{136}$Ba via laser-fluorescence spectroscopy and mass spectrometry. Simultaneously, an accelerator-driven Ba ion source is being developed to validate and optimize this technique. The motivation for the project, the development of the different aspects along with current status and results are discussed here.

Published
2024

3. Signal processing and spectral modeling for the BeEST experiment

Author

Kim, Inwook, Bray, Connor, Marino, Andrew, Stone-Whitehead, Caitlyn, Lamm, Amii, Abells, Ryan, Amaro, Pedro, Andoche, Adrien, Cantor, Robin, Diercks, David, Fretwell, Spencer, Gillespie, Abigail, Guerra, Mauro, Hall, Ad, Harris, Cameron N., Harris, Jackson T., Hinkle, Calvin, Hayen, Leendert M., Hervieux, Paul-Antoine, Kim, Geon-Bo, Leach, Kyle G., Lennarz, Annika, Lordi, Vincenzo, Machado, Jorge, McKeen, David, Mougeot, Xavier, Ponce, Francisco, Ruiz, Chris, Samanta, Amit, Santos, José Paulo, Smolsky, Joseph, Taylor, John, Templet, Joseph, Upadhyayula, Sriteja, Wagner, Louis, Warburton, William K., Waters, Benjamin, and Friedrich, Stephan

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

The Beryllium Electron capture in Superconducting Tunnel junctions (BeEST) experiment searches for evidence of heavy neutrino mass eigenstates in the nuclear electron capture decay of $^7$Be by precisely measuring the recoil energy of the $^7$Li daughter. In Phase-III, the BeEST experiment has been scaled from a single superconducting tunnel junction (STJ) sensor to a 36-pixel array to increase sensitivity and mitigate gamma-induced backgrounds. Phase-III also uses a new continuous data acquisition system that greatly increases the flexibility for signal processing and data cleaning. We have developed procedures for signal processing and spectral fitting that are sufficiently robust to be automated for large data sets. This article presents the optimized procedures before unblinding the majority of the Phase-III data set to search for physics beyond the standard model.

Published
2024

4. Imaging of single barium atoms in a second matrix site in solid xenon for barium tagging in a $^{136}$Xe double beta decay experiment

Author

Yvaine, M., Fairbank, D., Soderstrom, J., Taylor, C., Stanley, J., Walton, T., Chambers, C., Iverson, A., Fairbank, W., Kharusi, S. Al, Amy, A., Angelico, E., Anker, A., Arnquist, I. J., Atencio, A., Bane, J., Belov, V., Bernard, E. P., Bhatta, T., Bolotnikov, A., Breslin, J., Breur, P. A., Brodsky, J. P., Brown, E., Brunner, T., Caden, E., Cao, G. F., Cesmecioglu, D., Chambers, E., Chana, B., Chernyak, D., Chiu, M., Collister, R., Cvitan, M., Daniels, T., Darroch, L., DeVoe, R., di Vacri, M. L., Dolinski, M. J., Eckert, B., Elbeltagi, M., Elmansali, R., Fatemighomi, N., Foust, B., Fu, Y. S., Gallacher, D., Gallice, N., Giacomini, G., Gillis, W., Gingras, C., Gornea, R., Gratta, G., Hardy, C. A., Hedges, S., Hein, E., Holt, J. D., Hoppe, E. W., Karelin, A., Keblbeck, D., Kotov, I., Kuchenkov, A., Kumar, K. S., Kwiatkowski, A. A., Larson, A., Latif, M. B., Leach, K. G., Lennarz, A., Leonard, D. S., Lewis, H., Li, G., Li, Z., Licciardi, C., Lindsay, R., MacLellan, R., Majidi, S., Malbrunot, C., Masbou, J., McMichael, K., Peregrina, M. Medina, Moe, M., Mong, B., Moore, D. C., Natzke, C. R., Ngwadla, X. E., Ni, K., Nolan, A., Nowicki, S. C., Ondze, J. C. Nzobadila, Odian, A., Orrell, J. L., Ortega, G. S., Overman, C. T., Pagani, L., Smalley, H. Peltz, Perna, A., Pocar, A., Radeka, V., Raguzin, E., Rasiwala, H., Ray, D., Rescia, S., Richardson, G., Ross, R., Rowson, P. C., Saldanha, R., Sangiorgio, S., Schwartz, S., Sekula, S., Si, L., Soma, A. K., Spadoni, F., Stekhanov, V., Sun, X. L., Thibado, S., Tidball, A., Totev, T., Triambak, S., Tsang, T., Tyuka, O. A., van Bruggen, E., Vidal, M., Walent, M., Wamba, K., Wang, H. W., Wang, Q. D., Wang, W., Wang, Y. G., Watts, M., Wehrfritz, M., Wen, L. J., Wichoski, U., Wilde, S., Worcester, M., Xu, H., Yang, L., Yu, M., and Zeldovich, O.

Subjects
Physics - Atomic Physics, High Energy Physics - Experiment, Nuclear Experiment
Abstract

Neutrinoless double beta decay is one of the most sensitive probes for new physics beyond the Standard Model of particle physics. One of the isotopes under investigation is $^{136}$Xe, which would double beta decay into $^{136}$Ba. Detecting the single $^{136}$Ba daughter provides a sort of ultimate tool in the discrimination against backgrounds. Previous work demonstrated the ability to perform single atom imaging of Ba atoms in a single-vacancy site of a solid xenon matrix. In this paper, the effort to identify signal from individual barium atoms is extended to Ba atoms in a hexa-vacancy site in the matrix and is achieved despite increased photobleaching in this site. Abrupt fluorescence turn-off of a single Ba atom is also observed. Significant recovery of fluorescence signal lost through photobleaching is demonstrated upon annealing of Ba deposits in the Xe ice. Following annealing, it is observed that Ba atoms in the hexa-vacancy site exhibit antibleaching while Ba atoms in the tetra-vacancy site exhibit bleaching. This may be evidence for a matrix site transfer upon laser excitation. Our findings offer a path of continued research toward tagging of Ba daughters in all significant sites in solid xenon., Comment: 9 pages, 8 figures

Published
2024

5. Proton inelastic scattering reveals deformation in 8He

Author

M. Holl, R. Kanungo, Z.H. Sun, G. Hagen, J.A. Lay, A.M. Moro, P. Navrátil, T. Papenbrock, M. Alcorta, D. Connolly, B. Davids, A. Diaz Varela, M. Gennari, G. Hackman, J. Henderson, S. Ishimoto, A.I. Kilic, R. Krücken, A. Lennarz, J. Liang, J. Measures, W. Mittig, O. Paetkau, A. Psaltis, S. Quaglioni, J.S. Randhawa, J. Smallcombe, I.J. Thompson, M. Vorabbi, and M. Williams

Subjects
Physics, QC1-999
Abstract

A measurement of proton inelastic scattering of 8He at 8.25A MeV at TRIUMF shows a resonance at 3.54(6) MeV with a width of 0.89(11) MeV. The energy of the state is in good agreement with coupled cluster and no-core shell model with continuum calculations, with the latter successfully describing the measured resonance width as well. Its differential cross section analyzed with phenomenological collective excitation form factor and microscopic coupled reaction channels framework consistently reveals a large deformation parameter β2 = 0.40(3), consistent with no-core shell model predictions of a large neutron deformation. This deformed double-closed shell at the neutron drip-line opens a new paradigm.

Published
2021
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6. Direct Experimental Constraints on the Spatial Extent of a Neutrino Wavepacket

Author

Smolsky, Joseph, Leach, Kyle G, Abells, Ryan, Amaro, Pedro, Andoche, Adrien, Borbridge, Keith, Bray, Connor, Cantor, Robin, Diercks, David, Fretwell, Spencer, Friedrich, Stephan, Gillespie, Abigail, Guerra, Mauro, Hall, Ad, Harris, Cameron N, Harris, Jackson T, Hinkle, Calvin, Lamm, Amii, Hayen, Leendert M, Hervieux, Paul-Antoine, Kim, Geon-Bo, Kim, Inwook, Lennarz, Annika, Lordi, Vincenzo, Machado, Jorge, Marino, Andrew, McKeen, David, Mougeot, Xavier, Ponce, Francisco, Ruiz, Chris, Samanta, Amit, Santos, José Paulo, Stone-Whitehead, Caitlyn, Taylor, John, Templet, Joseph, Upadhyayula, Sriteja, Wagner, Louis, and Warburton, William K

Subjects
Nuclear Experiment, High Energy Physics - Experiment, Quantum Physics
Abstract

Despite their high relative abundance in our Universe, neutrinos are the least understood fundamental particles of nature. They also provide a unique system to study quantum coherence and the wavelike nature of particles in fundamental systems due to their extremely weak interaction probabilities. In fact, the quantum properties of neutrinos emitted in experimentally relevant sources are virtually unknown and the spatial extent of the neutrino wavepacket is only loosely constrained by reactor neutrino oscillation data with a spread of 13 orders of magnitude. Here, we present the first direct limits of this quantity through a new experimental concept to extract the energy width, $\sigma_{\textrm{N},E}$, of the recoil daughter nucleus emitted in the nuclear electron capture (EC) decay of $^7$Be. The final state in the EC decay process contains a recoiling $^7$Li nucleus and an electron neutrino ($\nu_e$) which are entangled at their creation. The $^7$Li energy spectrum is measured to high precision by directly embedding $^7$Be radioisotopes into a high resolution superconducting tunnel junction that is operated as a cryogenic sensor. The lower limit on the spatial uncertainty of the recoil daughter was found to be $\sigma_{\textrm{N}, x} \geq 6.2$\,pm, which implies the final-state system is localized at a scale more than a thousand times larger than the nucleus itself. From this measurement, the first direct lower limits on the spatial extent of the neutrino wavepacket were extracted using two different theoretical methods. These results have wide-reaching implications in several areas including the nature of spatial localization at sub-atomic scales, interpretation of neutrino physics data, and the potential reach of future large-scale experiments., Comment: 20 pages, 3 figures, v3 corrects and updates one of the wavepacket width calculations

Published
2024

7. First inverse kinematics measurement of key resonances in the 22Ne(p,γ)23Na reaction at stellar temperatures

Author

A. Lennarz, M. Williams, A.M. Laird, U. Battino, A.A. Chen, D. Connolly, B. Davids, N. Esker, R. Garg, M. Gay, U. Greife, U. Hager, D. Hutcheon, J. José, M. Lovely, S. Lyons, A. Psaltis, J.E. Riley, A. Tattersall, and C. Ruiz

Subjects
Inverse kinematics measurements, Radiative capture reactions, Stellar nucleosynthesis, Physics, QC1-999
Abstract

In this Letter we report on the first inverse kinematics measurement of key resonances in the Ne22(p,γ)23Na reaction which forms part of the NeNa cycle, and is relevant for 23Na synthesis in asymptotic giant branch (AGB) stars. An anti-correlation in O and Na abundances is seen across all well-studied globular clusters (GC), however, reaction-rate uncertainties limit the precision as to which stellar evolution models can reproduce the observed isotopic abundance patterns. Given the importance of GC observations in testing stellar evolution models and their dependence on NeNa reaction rates, it is critical that the nuclear physics uncertainties on the origin of 23Na be addressed. We present results of direct strengths measurements of four key resonances in Ne22(p,γ)23Na at Ec.m. = 149 keV, 181 keV, 248 keV and 458 keV. The strength of the important Ec.m. = 458 keV reference resonance has been determined independently of other resonance strengths for the first time with an associated strength of ωγ = 0.439(22) eV and with higher precision than previously reported. Our result deviates from the two most recently published results obtained from normal kinematics measurements performed by the LENA and LUNA collaborations but is in agreement with earlier measurements. The impact of our rate on the Na-pocket formation in AGB stars and its relation to the O-Na anti-correlation was assessed via network calculations. Further, the effect on isotopic abundances in CO and ONe novae ejecta with respect to pre-solar grains was investigated.

Published
2020
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8. First measurement in the Gamow window of a reaction for the γ-process in inverse kinematics: 76Se(α,γ)80Kr

Author

J. Fallis, C. Akers, A.M. Laird, A. Simon, A. Spyrou, G. Christian, D. Connolly, U. Hager, D.A. Hutcheon, A. Lennarz, P. O'Malley, S.J. Quinn, J. Riley, A. Rojas, C. Ruiz, and M. Williams

Subjects
Physics, QC1-999
Abstract

The p-nuclei are the few stable nuclei heavier than iron on the neutron-deficient side of the valley of stability that cannot be produced through astrophysical neutron-capture reactions. The limited experimental data on reactions through which the p-nuclei might be produced leaves the origin of their production largely unknown. This work presents the first cross section measurements of the 76Se(α,γ)80Kr reaction. The rate of the time reversed reaction, 80Kr(γ,α)76Se, is one of the most uncertain of possible reactions which can occur at the 80Kr branching point on the γ-process photo-disintegration pathway. The reaction flow through 80Kr will directly affect the final abundance of the p-nuclide 78Kr. Experimental cross sections at two astrophysically relevant energies are reported and compared to cross sections calculated using Hauser-Feshbach codes talys, non-smoker, and smaragd. The success of these first (α,γ) cross section measurements performed in inverse kinematics in the energy region of the γ-process opens the door for future studies of reactions on radioactive γ-process nuclides.

Published
2020
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9. The Data Acquisition System for Phase-III of the BeEST Experiment

Author

Bray, C., Fretwell, S., Kim, I., Warburton, W. K., Ponce, F., Leach, K. G., Friedrich, S., Abells, R., Amaro, P., Andoche, A., Cantor, R., Diercks, D., Guerra, M., Hall, A., Harris, C., Harris, J., Hayen, L., Hervieux, P. A., Kim, G. B., Lennarz, A., Lordi, V., Machado, J., Machule, P., Marino, A., McKeen, D., Mougeot, X., Ruiz, C., Samanta, A., Santos, J. P., and Stone-Whitehead, C.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment, Quantum Physics
Abstract

The BeEST experiment is a precision laboratory search for physics beyond the standard model that measures the electron capture decay of $^7$Be implanted into superconducting tunnel junction (STJ) detectors. For Phase-III of the experiment, we constructed a continuously sampling data acquisition system to extract pulse shape and timing information from 16 STJ pixels offline. Four additional pixels are read out with a fast list-mode digitizer, and one with a nuclear MCA already used in the earlier limit-setting phases of the experiment. We present the performance of the data acquisition system and discuss the relative advantages of the different digitizers., Comment: 8 pages, 4 figures, proceedings for The 20th International Conference on Low Temperature Detectors

Published
2023

11. A Contribution of the HAWC Observatory to the TeV era in the High Energy Gamma-Ray Astrophysics: The case of the TeV-Halos

Author

Torres-Escobedo, Ramiro, Zhou, Hao, de la Fuente, Eduardo, Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Baghmanyan, V., Barber, A. S., Gonzalez, J. Becerra, Belmont-Moreno, E., BenZvi, S. Y., Berley, D., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, de León, C., Diaz-Cruz, L., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., Durocher, M., DuVernois, M. A., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Alonso, M. Fernández, Fick, B., Fleischhack, H., Flores, J. L., Fraija, N. I., Garcia, D., García-González, J. A., García-Torales, G., Garfias, F., Giacinti, G., Goksu, H., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Herzog, I., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hui, C. M., Humensky, B., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Jhee, H., Joshi, V., Kieda, D., Kunde, G J., Kunwar, S., Lara, A., Lee, J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J., Longinotti, A. L., López-Coto, R., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Martinez, O., Martinez-Castellanos, I., Martínez-Huerta, H., Martínez-Castro, J., Matthews, J. A. J., McEnery, J., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rivière, C., Rosa-Gonzalez, D., Ruiz-Velasco, E., Ryan, J., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tanner, M., Tollefson, K., Torres, I., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Watson, I. J., Weisgarber, T., Werner, F., Willox, E., Wood, J., Yodh, G. B., and Zepeda, A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present a short overview of the TeV-Halos objects as a discovery and a relevant contribution of the High Altitude Water \v{C}erenkov (HAWC) observatory to TeV astrophysics. We discuss history, discovery, knowledge, and the next step through a new and more detailed analysis than the original study in 2017. TeV-Halos will contribute to resolving the problem of the local positron excess observed on the Earth. To clarify the latter, understanding the diffusion process is mandatory., Comment: Work presented in the 21st International Symposium on Very High Energy Cosmic Ray Interactions(ISVHECRI 2022) as part of the Ph. D. Thesis of Ramiro Torres-Escobedo (SJTU, Shanghai, China). Accepted for publication in SciPost Physics Proceedings (ISSN 2666-4003). 11 pages, 3 Figures. Short overview of HAWC and TeV Halos objects until 2022

Published
2023

12. The High-Altitude Water Cherenkov (HAWC) Observatory in M\'exico: The Primary Detector

Author

Abeysekara, A. U., Albert, A., Alfaro, R., Álvarez, C., Álvarez, J. D., Araya, M., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Barber, A. S., Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Blanco, O., Braun, J., Brisbois, C., Caballero-Mora, K. S., Martínez, J. I. Cabrera, Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, de la Fuente, E., de León, C., De Young, T., Hernández, R. Díaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Fick, U. B., Fleischhack, H., Flores, J. L., Fraija, N., García-González, J. A., García-Torales, G., Garfias, F., Giacinti, G., Goksu, H., González, M. M., González-Muñoz, A., Goodman, J. A., Harding, J. P., Hernández, E., Hernández, S., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hui, C. M., Humensky, T. B., Hüntemeyer, P., Iriarte, A., Imran, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Kunde, G. J., Lara, A., Lauer, R., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Marinelli, A., Martínez, O., Martínez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Montaruli, T., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Oceguera-Becerra, T., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Ponce, E., Pretz, J., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Sinnis, G., Smith, A. J., Son, Y., Woodle, K. Sparks, Springer, R. W., Taboada, I., Tepe, A., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Ukwatta, T. N., Varela, E., Vargas-Magaña, M., Villaseñor, L., Wang, X., Watson, I. J., Werner, F., Westerhoff, S., Willox, E., Wisher, I., Wood, J., Yodh, G. B., Zaborov, D., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The High-Altitude Water Cherenkov (HAWC) observatory is a second-generation continuously operated, wide field-of-view, TeV gamma-ray observatory. The HAWC observatory and its analysis techniques build on experience of the Milagro experiment in using ground-based water Cherenkov detectors for gamma-ray astronomy. HAWC is located on the Sierra Negra volcano in M\'exico at an elevation of 4100 meters above sea level. The completed HAWC observatory principal detector (HAWC) consists of 300 closely spaced water Cherenkov detectors, each equipped with four photomultiplier tubes to provide timing and charge information to reconstruct the extensive air shower energy and arrival direction. The HAWC observatory has been optimized to observe transient and steady emission from sources of gamma rays within an energy range from several hundred GeV to several hundred TeV. However, most of the air showers detected are initiated by cosmic rays, allowing studies of cosmic rays also to be performed. This paper describes the characteristics of the HAWC main array and its hardware., Comment: Accepted for publications in Nuclear Inst. and Methods in Physics Research, A (2023) 168253 ( https://www.sciencedirect.com/science/article/abs/pii/S0168900223002437 ); 39 pages, 14 Figures

Published
2023
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13. Cross Sections of the $^{83}$Rb(p,$\gamma)^{84}$Sr and $^{84}$Kr(p,$\gamma)^{85}$Rb Reactions at Energies Characteristic of the Astrophysical $\gamma$ Process

Author

Williams, M., Davids, B., Lotay, G., Nishimura, N., Rauscher, T., Gillespie, S. A., Alcorta, M., Amthor, A. M., Ball, G. C., Bhattacharjee, S. S., Bildstein, V., Catford, W. N., Doherty, D. T., Esker, N. E., Garnsworthy, A. B., Hackman, G., Hudson, K., Lennarz, A., Natzke, C., Olaizola, B., Psaltis, A., Svensson, C. E., Williams, J., Walter, D., and Yates, D.

Subjects
Nuclear Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

We have measured the cross section of the $^{83}$Rb(p,$\gamma)^{84}$Sr radiative capture reaction in inverse kinematics using a radioactive beam of $^{83}$Rb at incident energies of 2.4 and $2.7 A$ MeV. Prior to the radioactive beam measurement, the $^{84}$Kr(p,$\gamma)^{85}$Rb radiative capture reaction was measured in inverse kinematics using a stable beam of $^{84}$Kr at an incident energy of $2.7 A$ MeV. The effective relative kinetic energies of these measurements lie within the relevant energy window for the $\gamma$ process in supernovae. The central values of the measured partial cross sections of both reactions were found to be $0.17-0.42$ times the predictions of statistical model calculations. Assuming the predicted cross section at other energies is reduced by the same factor leads to a slightly higher calculated abundance of the $p$ nucleus $^{84}$Sr, caused by the reduced rate of the $^{84}$Sr($\gamma$,p)$^{83}$Rb reaction derived from the present measurement., Comment: 11 pages, 11 figures. arXiv admin note: text overlap with arXiv:2109.06775

Published
2023
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14. 'Searching for a needle in a haystack;' A Ba-tagging approach for an upgraded nEXO experiment

Author

Rasiwala, H., Murray, K., Lan, Y., Chambers, C., Cvitan, M., Brunner, T., Collister, R., Daniels, T., Elmansali, R., Fairbank, W., Gornea, R., Gratta, G., Koffas, T., Kwiatkowski, A. A., Leach, K. G., Lennarz, A., Malbrunot, C., Ray, D., Shaikh, R., and Yang, L.

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

nEXO is a proposed experiment that will search for neutrinoless double-beta decay (0$\nu\beta\beta$) in 5-tonnes of liquid xenon (LXe), isotopically enriched in $^{136}$Xe. A technique called Ba-tagging is being developed as a potential future upgrade for nEXO to detect the $^{136}$Xe double-beta decay daughter isotope, $^{136}$Ba. An efficient Ba-tagging technique has the potential to boost nEXO's 0$\nu\beta\beta$ sensitivity by essentially suppressing non-double-beta decay background events. A conceptual approach for the extraction from the detector volume, trapping, and identification of a single Ba ion from 5 tonnes of LXe is presented, along with initial results from the commissioning of one of its subsystems, a quadrupole mass filter., Comment: 4 pages, 2 figures

Published
2023
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15. Understanding globular cluster abundances through nuclear reactions

Author

Adsley, P, Williams, M, Harrouz, D S, Carrasco-Rojas, D P, de Séréville, N, Hammache, F, Longland, R, Bastin, B, Davids, B, Faestermann, T, Fougères, C, Greife, U, Hertenberger, R, Hutcheon, D, La Cognata, M, Laird, AM, Lamia, L, Lennarz, A, Meyer, A, Santos, F d'Oliveira, Palmerini, S, Psaltis, A, Pizzone, R G, Romano, S, Ruiz, C, Tumino, A, and Wirth, H-F

Subjects
Nuclear Experiment, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Nuclear Theory
Abstract

Globular clusters contain multiple stellar populations, with some previous generation of stars polluting the current stars with heavier elements. Understanding the history of globular clusters is helpful in understanding how galaxies merged and evolved and therefore constraining the site or sites of this historic pollution is a priority. The acceptable temperature and density conditions of these polluting sites depend on critical reaction rates. In this paper, three experimental studies helping to constrain astrophysically important reaction rates are briefly discussed., Comment: Submission to conference proceedings of INPC2022 in Cape Town

Published
2022

16. Elastic scattering of 3He+4He with SONIK

Author

Paneru, S. N., Brune, C. R., Connolly, D., Odell, D., Poudel, M., Phillips, D. R., Karpesky, J., Davids, B., Ruiz, C., Lennarz, A., Greife, U., Alcorta, M., Giri, R., Lovely, M., Bowry, M., Delgado, M., Esker, N. E., Garnsworthy, A., Seeman, C., Machule, P., Fallis, J., Chen, A. A., Laddaran, F., Firmino, A., and Weinerman, C.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Measurements of the elastic scattering cross section of 3He and 4He are important in order to improve constraints on theoretical models of 4He(3He,g)7Be, a key reaction in Big Bang nucleosynthesis and solar neutrino production. The astrophysical S-factor for this reaction is a significant source of uncertainty in the standard solar-model prediction of the 7Be and 8B solar neutrino fluxes. The elastic scattering measurements reported in the literature do not extend to low energies and lack proper uncertainty quantification. A new measurement of the 4He(3He,3He)4He reaction has been made at center-of-mass energies Ec.m. = 0.38-3.13 MeV using the Scattering of Nuclei in Inverse Kinematics (SONIK) scattering chamber: a windowless, extended gas target surrounded by an array of 30 collimated silicon charged particle detectors situated at TRIUMF. This is the first elastic scattering measurement of 3He+4He made below 500 keV and it has greater angular range and better precision than previous measurements. The elastic scattering data were analyzed using both R-matrix and Halo Effective Field Theory (Halo EFT) frameworks, and values of the s-wave scattering length and effective range were extracted. The resulting improvement in knowledge of the s-wave effective-range function at low energies will reduce the overall uncertainty in S34 at solar energies., Comment: 21 pages, 16 figures

Published
2022

17. First inverse kinematics measurement of resonances in $^7$Be($\alpha,\gamma$)$^{11}$C relevant to neutrino-driven wind nucleosynthesis using DRAGON

Author

Psaltis, A., Chen, A. A., Longland, R., Connolly, D. S., Brune, C. R., Davids, B., Fallis, J., Giri, R., Greife, U, Hutcheon, D. A., Kroll, L., Lennarz, A., Liang, J., Lovely, M., Luo, M., Marshall, C., Paneru, S. N., Parikh, A., Ruiz, C., Shotter, A. C., and Williams, M.

Subjects
Nuclear Experiment, Astrophysics - High Energy Astrophysical Phenomena
Abstract

A possible mechanism to explain the origin of the light $p$-nuclei in the Galaxy is the nucleosynthesis in the proton-rich neutrino-driven wind ejecta of core-collapse supernovae via the $\nu p$-process. However this production scenario is very sensitive to the underlying supernova dynamics and the nuclear physics input. As far as the nuclear uncertainties are concerned, the breakout from the $pp$-chains via the $^7$Be($\alpha,\gamma$)$^{11}$C reaction has been identified as an important link which can influence the nuclear flow and therefore the efficiency of the $\nu p$-process. However its reaction rate is poorly known over the relevant temperature range, T = 1.5-3 GK. We report on the first direct measurement of two resonances of the $^7$Be($\alpha,\gamma$)$^{11}$C reaction with previously unknown strengths using an intense radioactive $^7$Be beam from the ISAC facility and the DRAGON recoil separator in inverse kinematics. We have decreased the $^7$Be($\alpha,\gamma$)$^{11}$C reaction rate uncertainty to $\sim$ 9.4-10.7% over the relevant temperature region., Comment: 15 pages, 12 figures. Accepted for publication in Phys. Rev. C

Published
2022

18. Direct measurement of resonances in $^7$Be($\alpha,\gamma$)$^{11}$C relevant to $\nu p$-process nucleosynthesis

Author

Psaltis, A., Chen, A. A., Longland, R., Connolly, D. S., Brune, C. R., Davids, B., Fallis, J., Giri, R., Greife, U, Hutcheon, D. A., Kroll, L., Lennarz, A., Liang, J., Lovely, M., Luo, M., Marshall, C., Paneru, S. N., Parikh, A., Ruiz, C., Shotter, A. C., and Williams, M.

Subjects
Nuclear Experiment, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We have performed the first direct measurement of two resonances of the $^7$Be($\alpha,\gamma$)$^{11}$C reaction with unknown strengths using an intense radioactive $^7$Be beam and the DRAGON recoil separator. We report on the first measurement of the 1155 and 1110 keV resonance strengths of $1.73 \pm 0.25(stat.) \pm 0.40(syst.)$ eV and $125 ^{+27}_{-25}(stat.) \pm 15(syst.)$ meV, respectively. The present results have reduced the uncertainty in the $^7$Be($\alpha,\gamma$)$^{11}$C reaction rate to $\sim$ 9.4-10.7% over T = 1.5-3 GK, which is relevant for nucleosynthesis in the neutrino-driven outflows of core-collapse supernovae ($\nu p$-process). We find no effect of the new, constrained reaction rate on $\nu p$-process nucleosynthesis., Comment: 5 pages, 3 figures. Accepted for publication in Phys. Rev. Lett

Published
2022

19. New measurement of the $E_{\mathrm{c.m.}}=323$ keV resonance in the $^{19}$F$($p,\gamma$)$^{20}$Ne reaction

Author

Williams, M., Adsley, P., Davids, B., Greife, U., Hutcheon, D., Karpesky, J., Lennarz, A., Lovely, M., and Ruiz, C.

Subjects
Nuclear Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

At temperatures below 0.1 GK the $^{19}$F$(p,\gamma)^{20}$Ne reaction is the only breakout path out of the CNO cycle. Experimental studies of this reaction are challenging from a technical perspective due to copious $\gamma$-ray background from the far stronger $^{19}$F$(p,\alpha)^{16}$O reaction channel. Here we present the first inverse kinematics study of the $^{19}$F$(p,\gamma)^{20}$Ne reaction, in which we measure the strength of the 323-keV resonance. We find a strength value of $\omega\gamma = 3.3^{+1.1}_{-0.9}$ meV, which is a factor of two larger than the most recent previous study. The discrepancy is likely the result of a direct to ground state transition which previous studies were not sensitive to. We also observe the transition to the first $2^{-}$ state, which has not been observed for this resonance in previous studies. A new thermonuclear reaction rate is calculated and compared with the literature., Comment: arXiv admin note: text overlap with arXiv:1910.01698

Published
2022
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20. Constraints on key $^{17}$O($\alpha,\gamma$)$^{21}$Ne resonances and impact on the weak s-process

Author

Williams, M., Laird, A. M., Choplin, A., Adsley, P., Davids, B., Greife, U., Hudson, K., Hutcheon, D., Lennarz, A., and Ruiz, C.

Subjects
Nuclear Experiment, Astrophysics - Solar and Stellar Astrophysics, Nuclear Theory
Abstract

The efficiency of the slow neutron-capture process in massive stars is strongly influenced by neutron-capture reactions on light elements. At low metallicity, $^{16}$O is an important neutron absorber, but the effectiveness of $^{16}$O as a light-element neutron poison is modified by competition between subsequent $^{17}$O$(\alpha,n)^{20}$Ne and $^{17}$O$(\alpha,\gamma)^{21}$Ne reactions. The strengths of key $^{17}$O$(\alpha,\gamma)^{21}$Ne resonances within the Gamow window for core helium burning in massive stars are not well constrained by experiment. This work presents more precise measurements of resonances in the energy range $E_{c.m.} = 612 - 1319$ keV. We extract resonance strengths of $\omega\gamma_{638} = 4.85\pm0.79$ $\mu$eV, $\omega\gamma_{721} = 13.0^{+3.3}_{-2.4}$ $\mu$eV, $\omega\gamma_{814} = 7.72\pm0.55$ meV and $\omega\gamma_{1318} = 136\pm 13$ meV, for resonances at $E_{c.m.} =$ 638, 721, 814 and 1318 keV, respectively. We also report an upper limit for the 612 keV resonance of $\omega\gamma<140$ neV ($95\%$ c.l.), which effectively rules out any significant contribution from this resonance to the reaction rate. From this work, a new $^{17}$O$(\alpha,\gamma)^{21}$Ne thermonuclear reaction rate is calculated and compared to the literature. The effect of present uncertainties in the $^{17}$O$(\alpha,\gamma)^{21}$Ne reaction rate on weak s-process yields are then explored using post-processing calculations based on a rotating $20M_{\odot}$ low-metallicity massive star. The resulting $^{17}$O$(\alpha,\gamma)^{21}$Ne reaction rate is lower with respect to the pre-existing literature and found to enhance weak s-process yields in rotating massive star models., Comment: Accepted in Physical Review C

Published
2022
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21. Horizons: Nuclear Astrophysics in the 2020s and Beyond

Author

Schatz, H., Reyes, A. D. Becerril, Best, A., Brown, E. F., Chatziioannou, K., Chipps, K. A., Deibel, C. M., Ezzeddine, R., Galloway, D. K., Hansen, C. J., Herwig, F., Ji, A. P., Lugaro, M., Meisel, Z., Norman, D., Read, J. S., Roberts, L. F., Spyrou, A., Tews, I., Timmes, F. X., Travaglio, C., Vassh, N., Abia, C., Adsley, P., Agarwal, S., Aliotta, M., Aoki, W., Arcones, A., Aryan, A., Bandyopadhyay, A., Banu, A., Bardayan, D. W., Barnes, J., Bauswein, A., Beers, T. C., Bishop, J., Boztepe, T., Côté, B., Caplan, M. E., Champagne, A. E., Clark, J. A., Couder, M., Couture, A., de Mink, S. E., Debnath, S., deBoer, R. J., Hartogh, J. den, Denissenkov, P., Dexheimer, V., Dillmann, I., Escher, J. E., Famiano, M. A., Farmer, R., Fisher, R., Fröhlich, C., Frebel, A., Fryer, C., Fuller, G., Ganguly, A. K., Ghosh, S., Gibson, B. K., Gorda, T., Gourgouliatos, K. N., Graber, V., Gupta, M., Haxton, W., Heger, A., Hix, W. R., Ho, W C. G., Holmbeck, E. M., Hood, A. A., Huth, S., Imbriani, G., Izzard, R. G., Jain, R., Jayatissa, H., Johnston, Z., Kajino, T., Kankainen, A., Kiss, G. G., Kwiatkowski, A., La Cognata, M., Laird, A. M., Lamia, L., Landry, P., Laplace, E., Launey, K. D., Leahy, D., Leckenby, G., Lennarz, A., Longfellow, B., Lovell, A. E., Lynch, W. G., Lyons, S. M., Maeda, K., Masha, E., Matei, C., Merc, J., Messer, B., Montes, F., Mukherjee, A., Mumpower, M., Neto, D., Nevins, B., Newton, W. G., Nguyen, L. Q., Nishikawa, K., Nishimura, N., Nunes, F. M., O'Connor, E., O'Shea, B. W., Ong, W-J., Pain, S. D., Pajkos, M. A., Pignatari, M., Pizzone, R. G., Placco, V. M., Plewa, T., Pritychenko, B., Psaltis, A., Puentes, D., Qian, Y-Z., Radice, D., Rapagnani, D., Rebeiro, B. M., Reifarth, R., Richard, A. L., Rijal, N., Roederer, I. U., Rojo, J. S., K, J. S, Saito, Y., Schwenk, A., Sergi, M. L., Sidhu, R. S., Simon, A., Sivarani, T., Skúladóttir, Á., Smith, M. S., Spiridon, A., Sprouse, T. M., Starrfield, S., Steiner, A. W., Strieder, F., Sultana, I., Surman, R., Szücs, T., Tawfik, A., Thielemann, F., Trache, L., Trappitsch, R., Tsang, M. B., Tumino, A., Upadhyayula, S., Martínez, J. O. Valle, Van der Swaelmen, M., Vázquez, C. Viscasillas, Watts, A., Wehmeyer, B., Wiescher, M., Wrede, C., Yoon, J., Zegers, R G. T., Zermane, M. A., and Zingale, M.

Subjects
Nuclear Experiment, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics, Nuclear Theory
Abstract

Nuclear Astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper summarizes progress and status of the field, the new open questions that have emerged, and the tremendous scientific opportunities that have opened up with major advances in capabilities across an ever growing number of disciplines and subfields that need to be integrated. We take a holistic view of the field discussing the unique challenges and opportunities in nuclear astrophysics in regards to science, diversity, education, and the interdisciplinarity and breadth of the field. Clearly nuclear astrophysics is a dynamic field with a bright future that is entering a new era of discovery opportunities., Comment: 96 pages. Submitted to Journal of Physics G

Published
2022
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22. Proton inelastic scattering reveals deformation in $^8$He

Author

Holl, M., Kanungo, R., Sun, Z. H., Hagen, G., Lay, J. A., Moro, A. M., Navrátil, P., Papenbrock, T., Alcorta, M., Connolly, D., Davids, B., Varela, A. Diaz, Gennari, M., Hackman, G., Henderson, J., Ishimoto, S., Kilic, A. I., Krücken, R., Lennarz, A., Liang, J., Measures, J., Mittig, W., Paetkau, O., Psaltis, A., Quaglioni, S., Randhawa, J. S., Smallcombe, J., Thompson, I. J., Vorabbi, M., and Williams, M.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

A measurement of proton inelastic scattering of $^8$He at $8.25A$~MeV at TRIUMF shows a resonance at 3.54(6)~MeV with a width of 0.89(11)~MeV. The energy of the state is in good agreement with coupled cluster and no-core shell model with continuum calculations, with the latter successfully describing the measured resonance width as well. Its differential cross section analyzed with phenomenological collective excitation form factor and microscopic coupled reaction channels framework consistently reveals a large deformation parameter $\beta_2$ = 0.40(3), consistent with no-core shell model predictions of a large neutron deformation. This deformed double-closed shell at the neutron drip-line opens a new paradigm., Comment: 9 pages, 5 figures. Accepted for publication in Physics Letters B

Published
2021
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23. The Status and Future of Direct Nuclear Reaction Measurements for Stellar Burning

Author

Aliotta, M., Buompane, R., Couder, M., Couture, A., deBoer, R. J., Formicola, A., Gialanella, L., Glorius, J., Imbriani, G., Junker, M., Langer, C., Lennarz, A., Litvinov, Yu. A., Liu, W. -P., Lugaro, M., Matei, C., Meisel, Z., Piersanti, L., Reifarth, R., Robertson, D., Simon, A., Straniero, O., Tumino, A., Wiescher, M., and Xu, Y.

Subjects
Nuclear Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

The study of stellar burning began just over 100 years ago. Nonetheless, we do not yet have a detailed picture of the nucleosynthesis within stars and how nucleosynthesis impacts stellar structure and the remnants of stellar evolution. Achieving this understanding will require precise direct measurements of the nuclear reactions involved. This report summarizes the status of direct measurements for stellar burning, focusing on developments of the last couple of decades, and offering a prospectus of near-future developments., Comment: Accepted to Journal of Physics G as a Major Report. Corresponding author: Zach Meisel (meisel@ohio.edu)

Published
2021
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24. First Direct Measurement of an Astrophysical p-Process Reaction Cross Section Using a Radioactive Ion Beam

Author

Lotay, G., Gillespie, S. A., Williams, M., Rauscher, T., Alcorta, M., Amthor, M., Andreoiu, C. A., Baal, D., Ball, G. C., Bhattacharjee, S. S., Behnamian, H., Bildstein, V., Burbadge, C., Catford, W. N., Doherty, D. T., Esker, N. E., Garcia, F. H., Garnsworthy, A. B., Hackman, G., Hallam, S., Hudson, K. A., Jazrawi, S., Kasanda, E., Kennington, A. R. L., Kim, Y. H., Lennarz, A., Lubna, R. S., Natzke, C. R., Nishimura, N., Olaizola, B., Paxman, C., Psaltis, A., Svensson, C. E., Williams, J., Wallis, B., Yates, D., Walter, D., and Davids, B.

Subjects
Nuclear Experiment
Abstract

We have performed the first direct measurement of the 83Rb(p,g) radiative capture reaction cross section in inverse kinematics using a radioactive beam of 83Rb at incident energies of 2.4 and 2.7 A MeV. The measured cross section at an effective relative kinetic energy of Ecm = 2.393 MeV, which lies within the relevant energy window for core collapse supernovae, is smaller than the prediction of statistical model calculations. This leads to the abundance of 84Sr produced in the astrophysical p process being higher than previously calculated. Moreover, the discrepancy of the present data with theoretical predictions indicates that further experimental investigation of p-process reactions involving unstable projectiles is clearly warranted., Comment: 6 pages, 4 figures, published in Physical Review Letters

Published
2021
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25. First direct measurement of $^{59}$Cu(p,$\alpha$)$^{56}$Ni: A step towards constraining the Ni-Cu cycle in the Cosmos

Author

Randhawa, J. S., Kanungo, R., Refsgaard, J., Mohr, P., Ahn, T., Alcorta, M., Andreoiu, C., Bhattacharjee, S. S., Davids, B., Christian, G., Chen, A. A., Coleman, R., Garrett, P., Grinyer, G. F., Fuakye, E. Gyabeng, Hackman, G., Jain, R., Kapoor, K., Krücken, R., Laffoley, A., Lennarz, A., Liang, J., Meisel, Z., Nikhil, N., Psaltis, A., Radich, A., Rocchini, M., Saei, N., Saxena, M., Singh, M., Svensson, C., Subramaniam, P., Talebitaher, A., Upadhyayula, S., Waterfield, C., Williams, J., and Williams, M.

Subjects
Nuclear Experiment
Abstract

Reactions on the proton-rich nuclides drive the nucleosynthesis in Core-Collapse Supernovae (CCSNe) and in X-ray bursts (XRBs). CCSNe eject the nucleosynthesis products to the interstellar medium and hence are a potential inventory of p-nuclei, whereas in XRBs nucleosynthesis powers the light curves. In both astrophysical sites the Ni-Cu cycle, which features a competition between $^{59}$Cu(p,$\alpha$)$^{56}$Ni and $^{59}$Cu(p,$\gamma$)$^{60}$Zn, could potentially halt the production of heavier elements. Here, we report the first direct measurement of $^{59}$Cu(p,$\alpha$)$^{56}$Ni using a re-accelerated $^{59}$Cu beam and cryogenic solid hydrogen target. Our results show that the reaction proceeds predominantly to the ground state of $^{56}$Ni and the experimental rate has been found to be lower than Hauser-Feshbach-based statistical predictions. New results hint that the $\nu p$-process could operate at higher temperatures than previously inferred and therefore remains a viable site for synthesizing the heavier elements.

Published
2021
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26. Proton inelastic scattering reveals deformation in 8He

Author

Holl, M, Kanungo, R, Sun, ZH, Hagen, G, Lay, JA, Moro, AM, Navrátil, P, Papenbrock, T, Alcorta, M, Connolly, D, Davids, B, Varela, A Diaz, Gennari, M, Hackman, G, Henderson, J, Ishimoto, S, Kilic, AI, Krücken, R, Lennarz, A, Liang, J, Measures, J, Mittig, W, Paetkau, O, Psaltis, A, Quaglioni, S, Randhawa, JS, Smallcombe, J, Thompson, IJ, Vorabbi, M, and Williams, M

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract

A measurement of proton inelastic scattering of 8He at 8.25A MeV at TRIUMF shows a resonance at 3.54(6) MeV with a width of 0.89(11) MeV. The energy of the state is in good agreement with coupled cluster and no-core shell model with continuum calculations, with the latter successfully describing the measured resonance width as well. Its differential cross section analyzed with phenomenological collective excitation form factor and microscopic coupled reaction channels framework consistently reveals a large deformation parameter β2 = 0.40(3), consistent with no-core shell model predictions of a large neutron deformation. This deformed double-closed shell at the neutron drip-line opens a new paradigm.

Published
2021

27. Beyond the acceptance limit of DRAGON: the case of the $\mathrm{^6Li(\alpha,\gamma)^{10}B}$ reaction

Author

Psaltis, A., Chen, A. A., Connolly, D. S., Davids, B., Gilardy, G., Giri, R., Greife, U, Huang, W., Hutcheon, D. A., Karpesky, J., Lennarz, A., Liang, J., Paneru, M. Lovely. S. N., Ruiz, C., Tenkila, G., and Williams, M.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

Radiative capture reactions play a pivotal role for our understanding of the origin of the elements in the cosmos. Recoil separators provide an effective way to study these reactions, in inverse kinematics, and take advantage of the use of radioactive ion beams. However, a limiting factor in the study of radiative capture reactions in inverse kinematics is the momentum spread of the product nuclei, which can result in an angular spread larger than the geometric acceptance of the separator. The DRAGON facility at TRIUMF is a versatile recoil separator, designed to study radiative capture reactions relevant to astrophysics in the $\mathrm{A \sim 10-30}$ region. In this work we present the first attempt to study with DRAGON a reaction, $\mathrm{^6Li(\alpha,\gamma)^{10}B}$ , for which the recoil angular spread exceeds DRAGON's acceptance. Our result is in good agreement with the literature value, showing that DRAGON can measure resonance strengths of astrophysically important reactions even when not all the recoils enter the separator., Comment: 11 pages, 8 figures, Accepted for publication in Nucl. Instrum. Methods. Phys. Res. A

Published
2020
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28. Limits on the Existence of sub-MeV Sterile Neutrinos from the Decay of $^7$Be in Superconducting Quantum Sensors

Author

Friedrich, S., Kim, G. B., Bray, C., Cantor, R., Dilling, J., Fretwell, S., Hall, J. A., Lennarz, A., Lordi, V., Machule, P., McKeen, D., Mougeot, X., Ponce, F., Ruiz, C., Samanta, A., Warburton, W. K., and Leach, K. G.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, Quantum Physics
Abstract

Sterile neutrinos are natural extensions to the standard model of particle physics and provide a possible portal to the dark sector. We report a new search for the existence of sub-MeV sterile neutrinos using the decay-momentum reconstruction technique in the decay of $^7$Be. The experiment measures the total energy of the $^7$Li daughter atom from the electron capture decay of $^7$Be implanted into sensitive superconducting tunnel junction (STJ) quantum sensors. This first experiment presents data from a single STJ operated at a low count rate for a net total of 28 days, and provides exclusion limits on sterile neutrinos in the mass range from 100 to 850 keV that improve upon previous work by up to an order of magnitude., Comment: 7 pages. 3 figures. Submitted to Physical Review Letters

Published
2020
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29. Direct measurement of the $^7$Be $L/K$ capture ratio in Ta-based superconducting tunnel junctions

Author

Fretwell, S., Leach, K. G., Bray, C., Kim, G. B., Dilling, J., Lennarz, A., Mougeot, X., Ponce, F., Ruiz, C., Stackhouse, J., and Friedrich, S.

Subjects
Nuclear Experiment, Astrophysics - Solar and Stellar Astrophysics, Nuclear Theory
Abstract

We report a high-statistics measurement of the $L/K$ orbital electron capture (EC) ratio in $^7$Be embedded in cryogenic Ta. The thin Ta film formed part of a high-resolution superconducting tunnel junction (STJ) radiation detector that was used to identify the signals from different decay channels. The measured $L/K$ capture ratio of 0.070(7) is significantly larger than the only previous measurement of this quantity and the theoretical predictions that include in-medium effects. This value is a uniquely sensitive probe of the 1s and 2s orbital overlaps with the nucleus, and is of relevance to nuclear and atomic physics, as well as Li production in novae and other astrophysical scenarios. This is the first experiment that uses STJs for nuclear-recoil detection, opening a new experimental avenue for low-energy precision measurements with rare isotopes., Comment: 5 pages, 3 figures

Published
2020
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30. First inverse kinematics study of the $^{22}$Ne$(p,\gamma)^{23}$Na reaction and its role in AGB star and classical nova nucleosynthesis

Author

Williams, M., Lennarz, A., Laird, A. M., Battino, U., Connolly, J. José D., Ruiz, C., Chen, A., Davids, B., Esker, N., Fulton, B. R., Garg, R., Gay, x M., Greife, U., Hager, U., Hutcheon, D., Lovely, M., Lyons, S., Psaltis, A., Riley, J. E., and Tattersall, A.

Subjects
Nuclear Experiment
Abstract

The abundances of sodium and oxygen are observed to be anti-correlated in all well-studied globular clusters. Asymptotic giant branch (AGB) stars undergoing hot bottom burning (HBB) are thought to be prime candidates for producing sodium-rich oxygen-poor material and expelling it into the cluster ISM. The 22Ne(p,gamma)23Na reaction has been shown to strongly influence the amount of 23Na produced during HBB. This reaction is also important for classical novae nucleosynthesis, with sensitivity studies showing that the abundances of several isotopes in the Ne-Al region are significantly altered when varying the reaction rate between available compilations. Here we present the first inverse kinematics measurements of key resonances strengths as well as the direct capture S-factor. Together, this study represents the largest centre of mass energy range (149-1222 keV) over which this reaction has been measured in a single experiment. Our results for low-energy resonances at Ecm=149, 181 and 248 keV are in good agreement with recent forward kinematics results; we also find a direct capture S-factor consistent with the literature value of 62 keV.b. However, in the case of the important reference resonance at Ecm = 458 keV we find a strength value of wg=0.44 +/- 0.02 eV, which is significantly lower than recent results. Using our new recommended rate we explore the impact of these results on both AGB star and classical novae nucleosynthesis. In the case of AGB stars we see very little abundance changes with respect to the rate included in the STARLIB-2013. However, we observe changes of up to a factor of 2 in isotopes produced in both the carbon-oxygen (CO) and oxygen-neon (ONe) classical novae models considered here. The 22Ne(p,gamma)23Na reaction rate is now sufficiently well constrained to not significantly contribute toward abundance uncertainties from classical novae nucleosynthesis models., Comment: 19 pages, 19 figures, 8 tables

Published
2019
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31. First inverse kinematics measurement of key resonances in the ${}^{22}\text{Ne}(p,\gamma)^{23}\text{Na}$ reaction at stellar temperatures

Author

Lennarz, A., Williams, M., Laird, A. M., Battino, U., Chen, A. A., Connolly, D., Davids, B., Esker, N., Garg, R., Gay, M., Greife, U., Hager, U., Hutcheon, D., José, J., Lovely, M., Lyons, S., Psaltis, A., Riley, J. E., Tattersall, A., and Ruiz, C.

Subjects
Nuclear Experiment
Abstract

In this Letter we report on the first inverse kinematics measurement of key resonances in the ${}^{22}\text{Ne}(p,\gamma)^{23}\text{Na}$ reaction which forms part of the NeNa cycle, and is relevant for ${}^{23}$Na synthesis in asymptotic giant branch (AGB) stars. An anti-correlation in O and Na abundances is seen across all well-studied globular clusters (GC), however, reaction-rate uncertainties limit the precision as to which stellar evolution models can reproduce the observed isotopic abundance patterns. Given the importance of GC observations in testing stellar evolution models and their dependence on NeNa reaction rates, it is critical that the nuclear physics uncertainties on the origin of ${}^{23}$Na be addressed. We present results of direct strengths measurements of four key resonances in ${}^{22}\text{Ne}(p,\gamma)^{23}\text{Na}$ at E$_{{\text c.m.}}$ = 149 keV, 181 keV, 248 keV and 458 keV. The strength of the important E$_{{\text c.m.}}$ = 458 keV reference resonance has been determined independently of other resonance strengths for the first time with an associated strength of $\omega\gamma$ = 0.439(22) eV and with higher precision than previously reported. Our result deviates from the two most recently published results obtained from normal kinematics measurements performed by the LENA and LUNA collaborations but is in agreement with earlier measurements. The impact of our rate on the Na-pocket formation in AGB stars and its relation to the O-Na anti-correlation was assessed via network calculations. Further, the effect on isotopic abundances in CO and ONe novae ejecta with respect to pre-solar grains was investigated., Comment: 6 pages, 5 figures, preprint for PRL submission

Published
2019
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32. HAWC Contributions to the 36th International Cosmic Ray Conference (ICRC2019)

Author

Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Barber, A. S., Gonzalez, J. Becerra, Belmont-Moreno, E., BenZvi, S. Y., Berley, D., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti12, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, Diaz-Cruz, L., Díaz-Vélez, J. C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Engel, K., Enríquez-Rivera, O., Espinoza, C., Alonso, M. Fernández, Fick, B., Fiorino, D. W., Fleischhack, H., Fraija, N., Galván-Gámez, A., García-González, J. A., Garcia-Luna, J. L., Garfias, F., Giacinti, G., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., López-Coto, R., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A. J., McEnery, J., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Ryan, J., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Tabachnick, E., Taboada, I., Tanner, M., Tollefson, K., Torres, I., Torres-Escobedo, R., Ukwatta, T. N., Vianello, G., Villaseñor, L., Weisgarber, T., Werner, F., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G. B., Younk, P. W., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

List of proceedings from the HAWC Collaboration presented at the 36th International Cosmic Ray Conference, 24 July - 1 August 2019, Madison, Wisconsin, USA., Comment: List of proceedings from the HAWC Collaboration presented at ICRC2019. Corrected typos in the index of the previous version. Follow the "HTML" link to access the list

Published
2019

33. Atmospheric Cherenkov Telescopes as a Potential Veto Array for Neutrino Astronomy

Author

Rysewyk, D., Lennarz, D., DeYoung, T., Auffenberg, J., Schaufel, M., Bretz, T., Wiebusch, C., and Nisa, M. U.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

The IceCube Neutrino Observatory has revealed the existence of sources of high-energy astrophysical neutrinos. However, identification of the sources is challenging because astrophysical neutrinos are difficult to separate from the background of atmospheric neutrinos produced in cosmic-ray-induced particle cascades in the atmosphere. The efficient detection of air showers in coincidence with detected neutrinos can greatly reduce those backgrounds and increase the sensitivity of neutrino telescopes. Imaging Air Cherenkov Telescopes (IACTs) are sensitive to gamma-ray-induced (and cosmic-ray-induced) air showers in the 50 GeV to 50 TeV range, and can therefore be used as background-identifiers for neutrino observatories. This paper describes the feasibility of an array of small scale, wide field-of-view, cost-effective IACTs as an air shower veto for neutrino astronomy. A surface array of 250 to 750 telescopes would significantly improve the performance of a cubic kilometer-scale detector like IceCube, at a cost of a few percent of the original investment. The number of telescopes in the array can be optimized based on astronomical and geometrical considerations., Comment: 33 pages, 10 figures. Published by Astropart. Phys

Published
2019
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34. Catching Element Formation In The Act

Author

Fryer, Chris L., Timmes, Frank, Hungerford, Aimee L., Couture, Aaron, Adams, Fred, Aoki, Wako, Arcones, Almudena, Arnett, David, Auchettl, Katie, Avila, Melina, Badenes, Carles, Baron, Eddie, Bauswein, Andreas, Beacom, John, Blackmon, Jeff, Blondin, Stephane, Bloser, Peter, Boggs, Steve, Boss, Alan, Brandt, Terri, Bravo, Eduardo, Brown, Ed, Brown, Peter, Budtz-Jorgensen, Steve Bruenn. Carl, Burns, Eric, Calder, Alan, Caputo, Regina, Champagne, Art, Chevalier, Roger, Chieffi, Alessandro, Chipps, Kelly, Cinabro, David, Clarkson, Ondrea, Clayton, Don, Coc, Alain, Connolly, Devin, Conroy, Charlie, Cote, Benoit, Couch, Sean, Dauphas, Nicolas, deBoer, Richard James, Deibel, Catherine, Denisenkov, Pavel, Desch, Steve, Dessart, Luc, Diehl, Roland, Doherty, Carolyn, Dominguez, Inma, Dong, Subo, Dwarkadas, Vikram, Fan, Doreen, Fields, Brian, Fields, Carl, Filippenko, Alex, Fisher, Robert, Foucart, Francois, Fransson, Claes, Frohlich, Carla, Fuller, George, Gibson, Brad, Giryanskaya, Viktoriya, Gorres, Joachim, Goriely, Stephane, Grebenev, Sergei, Grefenstette, Brian, Grohs, Evan, Guillochon, James, Harpole, Alice, Harris, Chelsea, Harris, J. Austin, Harrison, Fiona, Hartmann, Dieter, Hashimoto, Masa-aki, Heger, Alexander, Hernanz, Margarita, Herwig, Falk, Hirschi, Raphael, Hix, Raphael William, Hoflich, Peter, Hoffman, Robert, Holcomb, Cole, Hsiao, Eric, Iliadis, Christian, Janiuk, Agnieszka, Janka, Thomas, Jerkstrand, Anders, Johns, Lucas, Jones, Samuel, Jose, Jordi, Kajino, Toshitaka, Karakas, Amanda, Karpov, Platon, Kasen, Dan, Kierans, Carolyn, Kippen, Marc, Korobkin, Oleg, Kobayashi, Chiaki, Kozma, Cecilia, Krot, Saha, Kumar, Pawan, Kuvvetli, Irfan, Laird, Alison, Laming, Martin, Larsson, Josefin, Lattanzio, John, Lattimer, James, Leising, Mark, Lennarz, Annika, Lentz, Eric, Limongi, Marco, Lippuner, Jonas, Livne, Eli, Lloyd-Ronning, Nicole, Longland, Richard, Lopez, Laura A., Lugaro, Maria, Lutovinov, Alexander, Madsen, Kristin, Malone, Chris, Matteucci, Francesca, McEnery, Julie, Meisel, Zach, Messer, Bronson, Metzger, Brian, Meyer, Bradley, Meynet, Georges, Mezzacappa, Anthony, Miller, Jonah, Miller, Richard, Milne, Peter, Misch, Wendell, Mitchell, Lee, Mosta, Philipp, Motizuki, Yuko, Muller, Bernhard, Mumpower, Matthew, Murphy, Jeremiah, Nagataki, Shigehiro, Nakar, Ehud, Nomoto, Ken'ichi, Nugent, Peter, Nunes, Filomena, O'Shea, Brian, Oberlack, Uwe, Pain, Steven, Parker, Lucas, Perego, Albino, Pignatari, Marco, Pinedo, Gabriel Martinez, Plewa, Tomasz, Poznanski, Dovi, Priedhorsky, William, Pritychenko, Boris, Radice, David, Ramirez-Ruiz, Enrico, Rauscher, Thomas, Reddy, Sanjay, Rehm, Ernst, Reifarth, Rene, Richman, Debra, Ricker, Paul, Rijal, Nabin, Roberts, Luke, Ropke, Friedrich, Rosswog, Stephan, Ruiter, Ashley J., Ruiz, Chris, Savin, Daniel Wolf, Schatz, Hendrik, Schneider, Dieter, Schwab, Josiah, Seitenzahl, Ivo, Shen, Ken, Siegert, Thomas, Sim, Stuart, Smith, David, Smith, Karl, Smith, Michael, Sollerman, Jesper, Sprouse, Trevor, Spyrou, Artemis, Starrfield, Sumner, Steiner, Andrew, Strong, Andrew W., Sukhbold, Tuguldur, Suntzeff, Nick, Surman, Rebecca, Tanimori, Toru, The, Lih-Sin, Thielemann, Friedrich-Karl, Tolstov, Alexey, Tominaga, Nozomu, Tomsick, John, Townsley, Dean, Tsintari, Pelagia, Tsygankov, Sergey, Vartanyan, David, Venters, Tonia, Vestrand, Tom, Vink, Jacco, Waldman, Roni, Wang, Lifang, Wang, Xilu, Warren, MacKenzie, West, Christopher, Wheeler, J. Craig, Wiescher, Michael, Winkler, Christoph, Winter, Lisa, Wolf, Bill, Woolf, Richard, Woosley, Stan, Wu, Jin, Wrede, Chris, Yamada, Shoichi, Young, Patrick, Zegers, Remco, Zingale, Michael, and Zwart, Simon Portegies

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays and relativistic-particle acceleration, and the evolution of galaxies. MeV gamma-rays provide a unique probe of nuclear processes in astronomy, directly measuring radioactive decay, nuclear de-excitation, and positron annihilation. The substantial information carried by gamma-ray photons allows us to see deeper into these objects, the bulk of the power is often emitted at gamma-ray energies, and radioactivity provides a natural physical clock that adds unique information. New science will be driven by time-domain population studies at gamma-ray energies. This science is enabled by next-generation gamma-ray instruments with one to two orders of magnitude better sensitivity, larger sky coverage, and faster cadence than all previous gamma-ray instruments. This transformative capability permits: (a) the accurate identification of the gamma-ray emitting objects and correlations with observations taken at other wavelengths and with other messengers; (b) construction of new gamma-ray maps of the Milky Way and other nearby galaxies where extended regions are distinguished from point sources; and (c) considerable serendipitous science of scarce events -- nearby neutron star mergers, for example. Advances in technology push the performance of new gamma-ray instruments to address a wide set of astrophysical questions., Comment: 14 pages including 3 figures

Published
2019

35. MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources

Author

Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Arcaro, C., Baack, D., Babić, A., Banerjee, B., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Berse, R. Ch., Berti, A., Bhattacharyya, W., Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Carosi, A., Ceribella, G., Chatterjee, A., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Ramazani, V. Fallah, Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Ishio, K., Konno, Y., Kubo, H., Kushida, J., Kuveždić, D., Lelas, D., Lindfors, E., Lombardi, S., Longo, F., López, M., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Mielke, K., Minev, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moreno, V., Moretti, E., Nagayoshi, T., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Peresano, M., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Stamerra, A., Strzys, M., Surić, T., Takahashi, M., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Treves, A., Tsujimoto, S., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Ward, J. E., Will, M., Zarić, D., Albert, A., Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Braun, J., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De León, C., De la Fuente, E., Hernandez, R. Diaz, Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., García-González, J. A., Garfias, F., González-Muñoz, A., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hueyotl-Zahuantitla, F., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-García, R., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Vianello, G., Villaseñor, L., Werner, F., Westerhoff, S., Wood, J., Yapici, T., Yodh, G., Zepeda, A., Zhou, H., Álvarez, J. D., Ajello, M., Baldini, L., Barbiellini, G., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bregeon, J., Bruel, P., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Chiaro, G., Ciprini, S., Costantin, D., D'Ammando, F., de Palma, F., Desai, A., Di Lalla, N., Di Mauro, M., Di Venere, L., Favuzzi, C., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Glanzman, T., Green, D., Grenier, I. A., Guiriec, S., Harding, A. K., Hays, E., Hewitt, J. W., Horan, D., Jóhannesson, G., Kuss, M., Larsson, S., Liodakis, I., Loparco, F., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Palatiello, M., Paliya, V. S., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Rainò, S., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Torresi, E., Troja, E., Valverde, J., Wood, K., and Yassine, M.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The HAWC Collaboration released the 2HWC catalog of TeV sources, in which 19 show no association with any known high-energy (HE; E > 10 GeV) or very-high-energy (VHE; E > 300 GeV) sources. This catalog motivated follow-up studies by both the MAGIC and Fermi-LAT observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between HAWC, MAGIC and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084* and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1 degree extension (at 95% confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, while a simply minimum extension of 0.16 degrees (at 95% confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail., Comment: 12 pages, 3 figures. Accepted for publication in MNRAS

Published
2019
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39. VERITAS and Fermi-LAT observations of new HAWC sources

Author

VERITAS Collaboration, Abeysekara, A. U., Archer, A., Benbow, W., Bird, R., Brose, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Chromey, A. J., Connolly, M. P., Cui, W., Daniel, M. K., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Hutten, M., Hanna, D., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Lin, T. T. Y., McArthur, S., Moriarty, P., Mukherjee, R., O'Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pohl, M., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Sushch, I., Tyler, J., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Williamson, T. J., Zitzer, B., Collaboration, Fermi-LAT, Abdollahi, S., Ajello, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Charles, E., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cutini, S., D'Ammando, F., de Palma, F., Di Lalla, N., Di Mauro, M., Di Venere, L., Dominguez, A., Favuzzi, C., Fegan, S. J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Hays, E., Hewitt, J. W., Horan, D., Johannesson, G., Kensei, S., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Mazziotta, M. N., McEnery, J. E., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Omodei, N., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Perkins, J. S., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Raino, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Tosti, G., Troja, E., Valverde, J., Vianello, G., Vogel, M., Wood, K., Yassine, M., Collaboration, HAWC, Alfaro, R., Alvarez, C., Alvarez, J. D., Arceo, R., Arteaga-Velazquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de Leon, S. Coutino, De Leon, C., De la Fuente, E., Dichiara, S., Dingus, B. L., DuVernois, M. A., Diaz-Velez, J. C., Engel, K., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., Garcia-Gonzalez, J. A., Garfias, F., Munoz, A. Gonzalez, Gonzalez, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hona, B., Hueyotl-Zahuantitla, F., Hui, C. M., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. Leon, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-Garcia, R., Lopez-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martinez-Castro, J., Martinez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Perez-Perez, E. G., Ren, Z., Rho, C. D., Riviere, C., Rosa-Gonzalez, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villasenor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The HAWC (High Altitude Water Cherenkov) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100~GeV) gamma-ray sources based on 507 days of observation. Among these, there are nineteen sources that are not associated with previously known TeV sources. We have studied fourteen of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1~TeV-30~TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected fourteen new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected GeV gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region., Comment: Accepted for publication in the ApJ, Corresponding author: Nahee Park (VERITAS Collaboration), John W. Hewitt (Fermi-LAT Collaboration), Ignacio Taboada (HAWC Collaboration), 30 pages, 12 figures

Published
2018
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40. Search for Dark Matter Gamma-ray Emission from the Andromeda Galaxy with the High-Altitude Water Cherenkov Observatory

Author

Albert, A., Alfaro, R., Alvarez, C., Alvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De León, C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Eckner, C., Engel, K., Enríquez-Rivera, O., Espinoza, C., Fiorino, D. W., Fraija, N., Galván-Gámez, A., García-González, J. A., Garfias, F., Muñoz, A. González, González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hona, B., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kunde, G. J., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Raya, G. Luis, Luna-García, R., Malone, K., Marinelli, S. S., Martinez, O., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Riviére, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wood, J., Yapici, T., Zaharijas, G., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Andromeda Galaxy (M31) is a nearby ($\sim$780 kpc) galaxy similar to our own Milky Way. Observational evidence suggests that it resides in a large halo of dark matter (DM), making it a good target for DM searches. We present a search for gamma rays from M31 using 1017 days of data from the High Altitude Water Cherenkov (HAWC) Observatory. With its wide field of view and constant monitoring, HAWC is well-suited to search for DM in extended targets like M31. No DM annihilation or decay signal was detected for DM masses from 1 to 100 TeV in the $b\bar{b}$, $t\bar{t}$, $\tau^{+}\tau^{-}$, $\mu^{+}\mu^{-}$, and $W^{+}W^{-}$ channels. Therefore we present limits on those processes. Our limits nicely complement the existing body of DM limits from other targets and instruments. Specifically the DM decay limits from our benchmark model are the most constraining for DM masses from 25 TeV to 100 TeV in the $b\bar{b}, t\bar{t}$ and $\mu^{+}\mu{-}$ channels. In addition to DM-specific limits, we also calculate general gamma-ray flux limits for M31 in 5 energy bins from 1 TeV to 100 TeV., Comment: published in JCAP. Figure 6 (bottom) has been corrected

Published
2018
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41. Computational Techniques for the Analysis of Small Signals in High-Statistics Neutrino Oscillation Experiments

Author

IceCube Collaboration, Aartsen, M. G., Ackermann, M., Adams, J., Aguilar, J. A., Ahlers, M., Ahrens, M., Samarai, I. Al, Altmann, D., Andeen, K., Anderson, T., Ansseau, I., Anton, G., Argüelles, C., Arlen, T. C., Auffenberg, J., Axani, S., Bagherpour, H., Bai, X., V., A. Balagopal, Barron, J. P., Bartos, I., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Tjus, J. Becker, Becker, K. -H., BenZvi, S., Berley, D., Bernardini, E., Besson, D. Z., Binder, G., Bindig, D., Blaufuss, E., Blot, S., Bohm, C., Bohmer, M., Börner, M., Bos, F., Böser, S., Botner, O., Bourbeau, E., Bourbeau, J., Bradascio, F., Braun, J., Brenzke, M., Bretz, H. -P., Bron, S., Brostean-Kaiser, J., Burgman, A., Busse, R. S., Carver, T., Cheung, E., Chirkin, D., Christov, A., Clark, K., Classen, L., Collin, G. H., Conrad, J. M., Coppin, P., Correa, P., Cowen, D. F., Cross, R., Dave, P., Day, M., de André, J. P. A. M., De Clercq, C., DeLaunay, J. J., Dembinski, H., De Ridder, S., Desiati, P., de Vries, K. D., de Wasseige, G., de With, M., DeYoung, T., Díaz-Vélez, J. C., di Lorenzo, V., Dujmovic, H., Dumm, J. P., Dunkman, M., DuVernois, M. A., Dvorak, E., Eberhardt, B., Ehrhardt, T., Eichmann, B., Eller, P., Engel, R., Evans, J. J., Evenson, P. A., Fahey, S., Fazely, A. R., Felde, J., Filimonov, K., Finley, C., Flis, S., Franckowiak, A., Friedman, E., Fritz, A., Gaisser, T. K., Gallagher, J., Gartner, A., Gerhardt, L., Gernhaeuser, R., Ghorbani, K., Giang, W., Glauch, T., Glüsenkamp, T., Goldschmidt, A., Gonzalez, J. G., Grant, D., Griffith, Z., Haack, C., Hallgren, A., Halzen, F., Hanson, K., Haugen, J., Haungs, A., Hebecker, D., Heereman, D., Helbing, K., Hellauer, R., Henningsen, F., Hickford, S., Hignight, J., Hill, G. C., Hoffman, K. D., Hoffmann, B., Hoffmann, R., Hoinka, T., Hokanson-Fasig, B., Holzapfel, K., Hoshina, K., Huang, F., Huber, M., Huber, T., Huege, T., Hultqvist, K., Hünnefeld, M., Hussain, R., In, S., Iovine, N., Ishihara, A., Jacobi, E., Japaridze, G. S., Jeong, M., Jero, K., Jones, B. J. P., Kalaczynski, P., Kalekin, O., Kang, W., Kang, D., Kappes, A., Kappesser, D., Karg, T., Karle, A., Katori, T., Katz, U., Kauer, M., Keivani, A., Kelley, J. L., Kheirandish, A., Kim, J., Kim, M., Kintscher, T., Kiryluk, J., Kittler, T., Klein, S. R., Koirala, R., Kolanoski, H., Köpke, L., Kopper, C., Kopper, S., Koschinsky, J. P., Koskinen, D. J., Kowalski, M., Krauss, C. B., Krings, K., Kroll, M., Krückl, G., Kunwar, S., Kurahashi, N., Kuwabara, T., Kyriacou, A., Labare, M., Lanfranchi, J. L., Larson, M. J., Lauber, F., Lennarz, D., Leonard, K., Lesiak-Bzdak, M., Leszczynska, A., Leuermann, M., Liu, Q. R., Lohfink, E., LoSecco, J., Mariscal, C. J. Lozano, Lu, L., Lünemann, J., Luszczak, W., Madsen, J., Maggi, G., Mahn, K. B. M., Mancina, S., Mandalia, S., Marka, S., Marka, Z., Maruyama, R., Mase, K., Maunu, R., Meagher, K., Medici, M., Meier, M., Menne, T., Merino, G., Meures, T., Miarecki, S., Micallef, J., Momenté, G., Montaruli, T., Moore, R. W., Moulai, M., Nahnhauer, R., Nakarmi, P., Naumann, U., Neer, G., Niederhausen, H., Nowicki, S. C., Nygren, D. R., Pollmann, A. Obertacke, Oehler, M., Olivas, A., O'Murchadha, A., O'Sullivan, E., Palazzo, A., Palczewski, T., Pandya, H., Pankova, D. V., Papp, L., Peiffer, P., Pepper, J. A., Heros, C. Pérez de los, Petersen, T. C., Pieloth, D., Pinat, E., Pinfold, J. L., Plum, M., Price, P. B., Przybylski, G. T., Raab, C., Rädel, L., Rameez, M., Rauch, L., Rawlins, K., Rea, I. C., Reimann, R., Relethford, B., Relich, M., Renschler, M., Resconi, E., Rhode, W., Richman, M., Riegel, M., Robertson, S., Rongen, M., Rott, C., Ruhe, T., Ryckbosch, D., Rysewyk, D., Safa, I., Sälzer, T., Herrera, S. E. Sanchez, Sandrock, A., Sandroos, J., Sandstrom, P., Santander, M., Sarkar, S., Satalecka, K., Schieler, H., Schlunder, P., Schmidt, T., Schneider, A., Schoenen, S., Schöneberg, S., Schröder, F. G., Schumacher, L., Sclafani, S., Seckel, D., Seunarine, S., Shaevitz, M. H., Soedingrekso, J., Soldin, D., Söldner-Rembold, S., Song, M., Spiczak, G. M., Spiering, C., Stachurska, J., Stamatikos, M., Stanev, T., Stasik, A., Stein, R., Stettner, J., Steuer, A., Stezelberger, T., Stokstad, R. G., Stößl, A., Strotjohann, N. L., Stuttard, T., Sullivan, G. W., Sutherland, M., Taboada, I., Taketa, A., Tanaka, H. K. M., Tatar, J., Tenholt, F., Ter-Antonyan, S., Terliuk, A., Tilav, S., Toale, P. A., Tobin, M. N., Tönnis, C., Toscano, S., Tosi, D., Tselengidou, M., Tung, C. F., Turcati, A., Turley, C. F., Ty, B., Unger, E., Usner, M., Vandenbroucke, J., Van Driessche, W., van Eijk, D., van Eijndhoven, N., Vanheule, S., van Santen, J., Veberic, D., Vogel, E., Vraeghe, M., Walck, C., Wallace, A., Wallraff, M., Wandler, F. D., Wandkowsky, N., Waza, A., Weaver, C., Weindl, A., Weiss, M. J., Wendt, C., Werthebach, J., Westerhoff, S., Whelan, B. J., Wiebe, K., Wiebusch, C. H., Wille, L., Williams, D. R., Wills, L., Wolf, M., Wood, J., Wood, T. R., Woolsey, E., Woschnagg, K., Wrede, G., Wren, S., Xu, D. L., Xu, X. W., Xu, Y., Yanez, J. P., Yodh, G., Yoshida, S., and Yuan, T.

Subjects
Physics - Data Analysis, Statistics and Probability, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract

The current and upcoming generation of Very Large Volume Neutrino Telescopes---collecting unprecedented quantities of neutrino events---can be used to explore subtle effects in oscillation physics, such as (but not restricted to) the neutrino mass ordering. The sensitivity of an experiment to these effects can be estimated from Monte Carlo simulations. With the high number of events that will be collected, there is a trade-off between the computational expense of running such simulations and the inherent statistical uncertainty in the determined values. In such a scenario, it becomes impractical to produce and use adequately-sized sets of simulated events with traditional methods, such as Monte Carlo weighting. In this work we present a staged approach to the generation of binned event distributions in order to overcome these challenges. By combining multiple integration and smoothing techniques which address limited statistics from simulation it arrives at reliable analysis results using modest computational resources.

Published
2018

42. Measurement of the multi-TeV neutrino cross section with IceCube using Earth absorption

Author

IceCube Collaboration, Aartsen, M. G., Ackermann, M., Adams, J., Aguilar, J. A., Ahlers, M., Ahrens, M., Samarai, I. Al, Altmann, D., Andeen, K., Anderson, T., Ansseau, I., Anton, G., Argüelles, C., Auffenberg, J., Axani, S., Bagherpour, H., Bai, X., Barron, J. P., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Tjus, J. Becker, Becker, K. -H., BenZvi, S., Berley, D., Bernardini, E., Besson, D. Z., Binder, G., Bindig, D., Blaufuss, E., Blot, S., Bohm, C., Börner, M., Bos, F., Bose, D., Böser, S., Botner, O., Bourbeau, J., Bradascio, F., Braun, J., Brayeur, L., Brenzke, M., Bretz, H. -P., Bron, S., Brostean-Kaiser, J., Burgman, A., Carver, T., Casey, J., Casier, M., Cheung, E., Chirkin, D., Christov, A., Clark, K., Classen, L., Coenders, S., Collin, G. H., Conrad, J. M., Cowen, D. F., Cross, R., Day, M., de André, J. P. A. M., De Clercq, C., DeLaunay, J. J., Dembinski, H., De Ridder, S., Desiati, P., de Vries, K. D., de Wasseige, G., de With, M., DeYoung, T., Díaz-Vélez, J. C., di Lorenzo, V., Dujmovic, H., Dumm, J. P., Dunkman, M., Eberhardt, B., Ehrhardt, T., Eichmann, B., Eller, P., Evenson, P. A., Fahey, S., Fazely, A. R., Felde, J., Filimonov, K., Finley, C., Flis, S., Franckowiak, A., Friedman, E., Fuchs, T., Gaisser, T. K., Gallagher, J., Gerhardt, L., Ghorbani, K., Giang, W., Glauch, T., Glüsenkamp, T., Goldschmidt, A., Gonzalez, J. G., Grant, D., Griffith, Z., Haack, C., Hallgren, A., Halzen, F., Hanson, K., Hebecker, D., Heereman, D., Helbing, K., Hellauer, R., Hickford, S., Hignight, J., Hill, G. C., Hoffman, K. D., Hoffmann, R., Hokanson-Fasig, B., Hoshina, K., Huang, F., Huber, M., Hultqvist, K., Hünnefeld, M., In, S., Ishihara, A., Jacobi, E., Japaridze, G. S., Jeong, M., Jero, K., Jones, B. J. P., Kalaczynski, P., Kang, W., Kappes, A., Karg, T., Karle, A., Katz, U., Kauer, M., Keivani, A., Kelley, J. L., Kheirandish, A., Kim, J., Kim, M., Kintscher, T., Kiryluk, J., Kittler, T., Klein, S. R., Kohnen, G., Koirala, R., Kolanoski, H., Köpke, L., Kopper, C., Kopper, S., Koschinsky, J. P., Koskinen, D. J., Kowalski, M., Krings, K., Kroll, M., Krückl, G., Kunnen, J., Kunwar, S., Kurahashi, N., Kuwabara, T., Kyriacou, A., Labare, M., Lanfranchi, J. L., Larson, M. J., Lauber, F., Lennarz, D., Lesiak-Bzdak, M., Leuermann, M., Liu, Q. R., Lu, L., Lünemann, J., Luszczak, W., Madsen, J., Maggi, G., Mahn, K. B. M., Mancina, S., Maruyama, R., Mase, K., Maunu, R., McNally, F., Meagher, K., Medici, M., Meier, M., Menne, T., Merino, G., Meures, T., Miarecki, S., Micallef, J., Momenté, G., Montaruli, T., Moore, R. W., Moulai, M., Nahnhauer, R., Nakarmi, P., Naumann, U., Neer, G., Niederhausen, H., Nowicki, S. C., Nygren, D. R., Pollmann, A. Obertacke, Olivas, A., O'Murchadha, A., Palczewski, T., Pandya, H., Pankova, D. V., Peiffer, P., Pepper, J. A., Heros, C. Pérez de los, Pieloth, D., Pinat, E., Plum, M., Price, P. B., Przybylski, G. T., Raab, C., Rädel, L., Rameez, M., Rawlins, K., Rea, I. C., Reimann, R., Relethford, B., Relich, M., Resconi, E., Rhode, W., Richman, M., Robertson, S., Rongen, M., Rott, C., Ruhe, T., Ryckbosch, D., Rysewyk, D., Sälzer, T., Herrera, S. E. Sanchez, Sandrock, A., Sandroos, J., Sarkar, S., Satalecka, K., Schlunder, P., Schmidt, T., Schneider, A., Schoenen, S., Schöneberg, S., Schumacher, L., Seckel, D., Seunarine, S., Soedingrekso, J., Soldin, D., Song, M., Spiczak, G. M., Spiering, C., Stachurska, J., Stamatikos, M., Stanev, T., Stasik, A., Stettner, J., Steuer, A., Stezelberger, T., Stokstad, R. G., Stößl, A., Strotjohann, N. L., Sullivan, G. W., Sutherland, M., Taboada, I., Tatar, J., Tenholt, F., Ter-Antonyan, S., Terliuk, A., Tešić, G., Tilav, S., Toale, P. A., Tobin, M. N., Toscano, S., Tosi, D., Tselengidou, M., Tung, C. F., Turcati, A., Turley, C. F., Ty, B., Unger, E., Usner, M., Vandenbroucke, J., Van Driessche, W., van Eijndhoven, N., Vanheule, S., van Santen, J., Vehring, M., Vogel, E., Vraeghe, M., Walck, C., Wallace, A., Wallraff, M., Wandler, F. D., Wandkowsky, N., Waza, A., Weaver, C., Weiss, M. J., Wendt, C., Werthebach, J., Westerhoff, S., Whelan, B. J., Wiebe, K., Wiebusch, C. H., Wille, L., Williams, D. R., Wills, L., Wolf, M., Wood, J., Wood, T. R., Woolsey, E., Woschnagg, K., Xu, D. L., Xu, X. W., Xu, Y., Yanez, J. P., Yodh, G., Yoshida, S., Yuan, T., and Zoll, M.

Subjects
High Energy Physics - Experiment, Astrophysics - High Energy Astrophysical Phenomena, Nuclear Experiment
Abstract

Neutrinos interact only very weakly, so they are extremely penetrating. However, the theoretical neutrino-nucleon interaction cross section rises with energy such that, at energies above 40 TeV, neutrinos are expected to be absorbed as they pass through the Earth. Experimentally, the cross section has been measured only at the relatively low energies (below 400 GeV) available at neutrino beams from accelerators \cite{Agashe:2014kda, Formaggio:2013kya}. Here we report the first measurement of neutrino absorption in the Earth, using a sample of 10,784 energetic upward-going neutrino-induced muons observed with the IceCube Neutrino Observatory. The flux of high-energy neutrinos transiting long paths through the Earth is attenuated compared to a reference sample that follows shorter trajectories through the Earth. Using a fit to the two-dimensional distribution of muon energy and zenith angle, we determine the cross section for neutrino energies between 6.3 TeV and 980 TeV, more than an order of magnitude higher in energy than previous measurements. The measured cross section is $1.30^{+0.21}_{-0.19}$ (stat.) $^{+0.39}_{-0.43}$ (syst.) times the prediction of the Standard Model \cite{CooperSarkar:2011pa}, consistent with the expectation for charged and neutral current interactions. We do not observe a dramatic increase in the cross section, expected in some speculative models, including those invoking new compact dimensions \cite{AlvarezMuniz:2002ga} or the production of leptoquarks \cite{Romero:2009vu}., Comment: Preprint version of Nature paper 10.1038/nature24459

Published
2017
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43. Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth

Author

Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Barber, A. S., Bautista-Elivar, N., Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Berley, D., Bernal, A., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De León, C., De la Fuente, E., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Enríquez-Rivera, O., Fiorino, D. W., Fraija, N., García-González, J. A., Garfias, F., Gerhardt, M., Muñoz, A. González, González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernández, S., Hernández-Almada, A., Hinton, J., Hona, B., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Raya, G. Luis, Luna-García, R., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Vianello, G., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G., Younk, P. W., Zepeda, A., Zhou, H., Guo, F., Hahn, J., Li, H., and Zhang, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The unexpectedly high flux of cosmic ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the HighAltitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin., Comment: 16 pages (including supplementary material), 5 figures

Published
2017
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44. A Search for Dark Matter in the Galactic Halo with HAWC

Author

Abeysekara, A. U., Albert, A. M., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., De León, C., De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Engel, K., Enríquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., García-González, J. A., Garfias, F., Muñoz, A. González, González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-García, R., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rodd, N. L., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Safdi, B. R., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Vianello, G., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G. B., Younk, P. W., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Phenomenology
Abstract

The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 500 GeV - 100 TeV gamma rays and cosmic rays. With its observations over 2/3 of the sky every day, the HAWC observatory is sensitive to a wide variety of astrophysical sources, including possible gamma rays from dark matter. Dark matter annihilation and decay in the Milky Way Galaxy should produce gamma-ray signals across many degrees on the sky. The HAWC instantaneous field-of-view of 2 sr enables observations of extended regions on the sky, such as those from dark matter in the Galactic halo. Here we show limits on the dark matter annihilation cross-section and decay lifetime from HAWC observations of the Galactic halo with 15 months of data. These are some of the most robust limits on TeV and PeV dark matter, largely insensitive to the dark matter morphology. These limits begin to constrain models in which PeV IceCube neutrinos are explained by dark matter which primarily decays into hadrons., Comment: 24 pages, 11 figures

Published
2017
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45. The IceCube Neutrino Observatory - Contributions to ICRC 2017 Part VI: IceCube-Gen2, the Next Generation Neutrino Observatory

Author

Collaboration, IceCube-Gen2, Aartsen, M. G., Ackermann, M., Adams, J., Aguilar, J. A., Ahlers, M., Ahrens, M., Samarai, I. Al, Altmann, D., Andeen, K., Anderson, T., Ansseau, I., Anton, G., Argüelles, C., Arlen, T. C., Auffenberg, J., Axani, S., Bagherpour, H., Bai, X., Balagopal, A. V., Barron, J. P., Bartos, I., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Tjus, J. Becker, Becker, K. -H., BenZvi, S., Berley, D., Bernardini, E., Besson, D. Z., Binder, G., Bindig, D., Blaufuss, E., Blot, S., Bohm, C., Bohmer, M., Börner, M., Bos, F., Bose, D., Böser, S., Botner, O., Bourbeau, J., Bradascio, F., Braun, J., Brayeur, L., Brenzke, M., Bretz, H. -P., Bron, S., Brostean-Kaiser, J., Burgman, A., Carver, T., Casey, J., Casier, M., Cheung, E., Chirkin, D., Christov, A., Clark, K., Classen, L., Coenders, S., Collin, G. H., Conrad, J. M., Cowen, D. F., Cross, R., Day, M., de André, J. P. A. M., De Clercq, C., DeLaunay, J. J., Dembinski, H., De Ridder, S., Desiati, P., de Vries, K. D., de Wasseige, G., de With, M., DeYoung, T., Díaz-Vélez, J. C., di Lorenzo, V., Dujmovic, H., Dumm, J. P., Dunkman, M., DuVernois, M. A., Eberhardt, B., Ehrhardt, T., Eichmann, B., Eller, P., Engel, R., Evans, J. J., Evenson, P. A., Fahey, S., Fazely, A. R., Felde, J., Filimonov, K., Finley, C., Flis, S., Franckowiak, A., Friedman, E., Fuchs, T., Gaisser, T. K., Gallagher, J., Gartner, A., Gerhardt, L., Gernhaeuser, R., Ghorbani, K., Giang, W., Glauch, T., Glüsenkamp, T., Goldschmidt, A., Gonzalez, J. G., Grant, D., Griffith, Z., Haack, C., Hallgren, A., Halzen, F., Hanson, K., Haugen, J., Haungs, A., Hebecker, D., Heereman, D., Helbing, K., Hellauer, R., Henningsen, F., Hickford, S., Hignight, J., Hill, G. C., Hoffman, K. D., Hoffmann, B., Hoffmann, R., Hokanson-Fasig, B., Holzapfel, K., Hoshina, K., Huang, F., Huber, M., Huber, T., Huege, T., Hultqvist, K., Hünnefeld, M., In, S., Ishihara, A., Jacobi, E., Japaridze, G. S., Jeong, M., Jero, K., Jones, B. J. P., Kalaczynski, P., Kalekin, O., Kang, W., Kang, D., Kappes, A., Karg, T., Karle, A., Katori, T., Katz, U., Kauer, M., Keivani, A., Kelley, J. L., Kheirandish, A., Kim, J., Kim, M., Kintscher, T., Kiryluk, J., Kittler, T., Klein, S. R., Kohnen, G., Koirala, R., Kolanoski, H., Köpke, L., Kopper, C., Kopper, S., Koschinsky, J. P., Koskinen, D. J., Kowalski, M., Krauss, C. B., Krings, K., Kroll, M., Krückl, G., Kunnen, J., Kunwar, S., Kurahashi, N., Kuwabara, T., Kyriacou, A., Labare, M., Lanfranchi, J. L., Larson, M. J., Lauber, F., Lennarz, D., Lesiak-Bzdak, M., Leszczynska, A., Leuermann, M., Liu, Q. R., LoSecco, J., Lu, L., Lünemann, J., Luszczak, W., Madsen, J., Maggi, G., Mahn, K. B. M., Mancina, S., Mandalia, S., Marka, S., Marka, Z., Maruyama, R., Mase, K., Maunu, R., McNally, F., Meagher, K., Medici, M., Meier, M., Menne, T., Merino, G., Meures, T., Miarecki, S., Micallef, J., Momenté, G., Montaruli, T., Moore, R. W., Moulai, M., Nahnhauer, R., Nakarmi, P., Naumann, U., Neer, G., Niederhausen, H., Nowicki, S. C., Nygren, D. R., Pollmann, A. Obertacke, Oehler, M., Olivas, A., O'Murchadha, A., Palazzo, A., Palczewski, T., Pandya, H., Pankova, D. V., Papp, L., Peiffer, P., Pepper, J. A., Heros, C. Pérez de los, Petersen, T. C., Pieloth, D., Pinat, E., Pinfold, J. L., Plum, M., Price, P. B., Przybylski, G. T., Raab, C., Rädel, L., Rameez, M., Rawlins, K., Rea, I. C., Reimann, R., Relethford, B., Relich, M., Renschler, M., Resconi, E., Rhode, W., Richman, M., Riegel, M., Robertson, S., Rongen, M., Rott, C., Ruhe, T., Ryckbosch, D., Rysewyk, D., Sälzer, T., Herrera, S. E. Sanchez, Sandrock, A., Sandroos, J., Sandstrom, P., Sarkar, S., Satalecka, K., Schieler, H., Schlunder, P., Schmidt, T., Schneider, A., Schoenen, S., Schöneberg, S., Schröder, F. G., Schumacher, L., Seckel, D., Seunarine, S., Shaevitz, M. H., Soedingrekso, J., Soldin, D., Söldner-Rembold, S., Song, M., Spiczak, G. M., Spiering, C., Stachurska, J., Stamatikos, M., Stanev, T., Stasik, A., Stettner, J., Steuer, A., Stezelberger, T., Stokstad, R. G., Stößl, A., Strotjohann, N. L., Sullivan, G. W., Sutherland, M., Taboada, I., Taketa, A., Tanaka, H. K. M., Tatar, J., Tenholt, F., Ter-Antonyan, S., Terliuk, A., Tešić, G., Tilav, S., Toale, P. A., Tobin, M. N., Toscano, S., Tosi, D., Tselengidou, M., Tung, C. F., Turcati, A., Turley, C. F., Ty, B., Unger, E., Usner, M., Vandenbroucke, J., Van Driessche, W., van Eijndhoven, N., Vanheule, S., van Santen, J., Veberic, D., Vehring, M., Vogel, E., Vraeghe, M., Walck, C., Wallace, A., Wallraff, M., Wandler, F. D., Wandkowsky, N., Waza, A., Weaver, C., Weindl, A., Weiss, M. J., Wendt, C., Werthebach, J., Westerhoff, S., Whelan, B. J., Wiebe, K., Wiebusch, C. H., Wille, L., Williams, D. R., Wills, L., Wolf, M., Wood, J., Wood, T. R., Woolsey, E., Woschnagg, K., Wren, S., Xu, D. L., Xu, X. W., Xu, Y., Yanez, J. P., Yodh, G., Yoshida, S., Yuan, T., and Zoll, M.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Papers on research & development towards IceCube-Gen2, the next generation neutrino observatory at South Pole, submitted to the 35th International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by the IceCube-Gen2 Collaboration.

Published
2017

46. All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

Author

HAWC Collaboration, Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Barber, A. S., Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De León, C., De la Fuente, E., Hernandez, R. Diaz, Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., García-González, J. A., Muñoz, A. González, González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez-Almada, A., Hinton, J., Hueyotl-Zahuantitla, F., Hui, C. M., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Raya, G. Luis, Luna-García, R., López-Cámara, D., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wood, J., Yapici, T., Zepeda, A., Zhou, H., and Álvarez, J. D.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of $-2.49\pm0.01$ prior to a break at $(45.7\pm0.1$) TeV, followed by an index of $-2.71\pm0.01$. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy., Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review D

Published
2017
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47. Search of extended or delayed TeV emission from GRBs with HAWC

Author

Dichiara, Simone, González, Maria Magdalena, Fraija, Nissim, Torres, Ibrahim, Becerril, Ana Delia, Alfaro, Ruben, and Lennarz, Dirk

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Gamma-ray bursts (GRBs) are among the most luminous sources in the universe and the nature of their emission up to very high energy is one of the most important open issue connected with the study of these peculiar events. The High Altitude Water Cherenkov (HAWC) gamma-ray observatory, installed at an altitude of 4100 m a. s. l. in the state of Puebla (Mexico), has completed its second year of full operations. Thanks to its instantaneous field of view of ~2 sr and its high duty cycle ($\ge$ 95%), HAWC is an ideal instrument for the study of transient phenomena such as GRBs. We performed a search for TeV emission delayed with respect to, and of longer duration than the prompt emission observed by satellites. We present here the results obtained by observing at the position of a sample of GRBs detected by the Fermi and Swift satellites from December 2014 to February 2017. The upper limits resulting from this analysis are presented and theoretical implications are discussed., Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contributions

Published
2017

48. Data Acquisition Architecture and Online Processing System for the HAWC gamma-ray observatory

Author

HAWC collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Gonzalez, J. Becerra, Belmont-Moreno, E., BenZvi, S. Y., Berley, D., Rosales, M. Bonilla, Braun, J., Caballero-Lopez, R. A., Caballero-Mora, K. S., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de la Fuente, E., De León, C., DeYoung, T., Diaz-Cruz, J., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Fiorino, D. W., Fraija, N., Galindo, A., Garfias, F., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Hampel-Arias, Z., Harding, J. P., Hui, C. M., Hüntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linares, E. C., Linnemann, J. T., Proper, M. Longo, Luna-García, R., Malone, K., Marinelli, A., Marinelli, S. S., Martinez, O., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A. J., McEnery, J., Torres, E. Mendoza, Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Rivière, C., Rosa-González, D., Ruiz-Velasco, E., Ryan, J., Salazar, H., Greus, F. Salesa, Sanchez, F. E., Sandoval, A., Schneider, M., Silich, S., Sinni, G., Smith, A. J., Woodle, K. Sparks, Springer, R. W., Taboada, I., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G. B., Younk, P. W., Zaborov, D., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The High Altitude Water Cherenkov observatory (HAWC) is an air shower array devised for TeV gamma-ray astronomy. HAWC is located at an altitude of 4100 m a.s.l. in Sierra Negra, Mexico. HAWC consists of 300 Water Cherenkov Detectors, each instrumented with 4 photomultiplier tubes (PMTs). HAWC re-uses the Front-End Boards from the Milagro experiment to receive the PMT signals. These boards are used in combination with Time to Digital Converters (TDCs) to record the time and the amount of light in each PMT hit (light flash). A set of VME TDC modules (128 channels each) is operated in a continuous (dead time free) mode. The TDCs are read out via the VME bus by Single-Board Computers (SBCs), which in turn are connected to a gigabit Ethernet network. The complete system produces ~ 500 MB/s of raw data. A high-throughput data processing system has been designed and built to enable real-time data analysis. The system relies on off-the-shelf hardware components, an open-source software technology for data transfers (ZeroMQ) and a custom software framework for data analysis (AERIE). Multiple trigger and reconstruction algorithms can be combined and run on blocks of data in a parallel fashion, producing a set of output data streams which can be analyzed in real time with minimal latency (< 5 s). This paper provides an overview of the hardware set-up and an in-depth description of the software design, covering both the TDC data acquisition system and the real-time data processing system. The performance of these systems is also discussed., Comment: 14 pages, 3 figures, submitted to Nucl. Instrum. Meth. A

Published
2017
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49. Gammapy - A prototype for the CTA science tools

Author

Deil, Christoph, Zanin, Roberta, Lefaucheur, Julien, Boisson, Catherine, Khélifi, Bruno, Terrier, Régis, Wood, Matthew, Mohrmann, Lars, Chakraborty, Nachiketa, Watson, Jason, Coto, Rubén López, Klepser, Stefan, Cerruti, Matteo, Lenain, Jean-Philippe, Acero, Fabio, Djannati-Ataï, Arache, Pita, Santiago, Bosnjak, Zeljka, Ruiz, José Enrique, Trichard, Cyril, Vuillaume, Thomas, Donath, Axel, King, Johannes, Jouvin, Léa, Owen, Ellis, Arribas, Manuel Paz, Sipocz, Brigitta, Lennarz, Dirk, Voruganti, Arjun, and Spir-Jacob, Marion

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Gammapy is a Python package for high-level gamma-ray data analysis built on Numpy, Scipy and Astropy. It enables us to analyze gamma-ray data and to create sky images, spectra and lightcurves, from event lists and instrument response information, and to determine the position, morphology and spectra of gamma-ray sources. So far Gammapy has mostly been used to analyze data from H.E.S.S. and Fermi-LAT, and is now being used for the simulation and analysis of observations from the Cherenkov Telescope Array (CTA). We have proposed Gammapy as a prototype for the CTA science tools. This contribution gives an overview of the Gammapy package and project and shows an analysis application example with simulated CTA data., Comment: Proc. 35th ICRC, Busan, South Korea, PoS(ICRC2017)766

Published
2017

50. HAWC Contributions to the 35th International Cosmic Ray Conference (ICRC2017)

Author

Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Barber, A. S., Gonzalez, J. Becerra, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Berley, D., Bernal, A., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Diaz-Cruz, L., Díaz-Vélez, J. C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Engel, K., Enriquez-Rivera, O., Fick, B., Fiorino, D. W., Fleischhack, H., Flores, J. L., Fraija, N., García-González, J. A., Garcia-Luna, J. L., Garcia-Torales, G., Garfias, F., Gerhardt, M., González, M. M., Muñoz, A. González, Goodman, J. A., Gussert, M., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hinton, J., Hona, B., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Proper, M. Longo, López-Coto, R., Raya, G. Luis, Luna-García, R., Malone, K., Marandon, V., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A. J., McEnery, J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Ryan, J., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Smith, A. W., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Vianello, G., Weisgarber, T., Westerhoff, S., Wood, J., Yapici, T., Yodh, G. B., Younk, P. W., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

List of proceedings from the HAWC Collaboration presented at the 35th International Cosmic Ray Conference, 12 July - 20 July 2017, Bexco, Busan, Korea., Comment: List of proceedings from the HAWC Collaboration presented at ICRC2017. Corrected typos in the index of the previous version. Follow the "HTML" link to access the list

Published
2017

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