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243 results on '"Yazdani, K"'

1. Extending light WIMP searches to single scintillation photons in LUX

Author: Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Baxter, A., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Boxer, B., Brás, P., Burdin, S., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., de Viveiros, L., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Genovesi, J., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Grace, E., Gwilliam, C., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Jahangir, O., Ji, W., Kamdin, K., Kazka, K., Khaitan, D., Knoche, R., Korolkova, E. V., Kravitz, S., Kudryavtsev, V. A., Larsen, N. A., Leason, E., Lee, C., Lenardo, B. G., Lesko, K. T., Levy, C., Liao, J., Lin, J., Lindote, A., Lopes, M. I., López-Paredes, B., Manalaysay, A., Mannino, R. L., Marangou, N., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Naylor, A., Nehrkorn, C., Nelson, H. N., Neves, F., Nilima, A., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Reichhart, L., Riffard, Q., Rischbieter, G. R. C., Rossiter, P., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, R., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Utku, U., Uvarov, S., Vacheret, A., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Woodward, D., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: We present a novel analysis technique for liquid xenon time projection chambers that allows for a lower threshold by relying on events with a prompt scintillation signal consisting of single detected photons. The energy threshold of the LUX dark matter experiment is primarily determined by the smallest scintillation response detectable, which previously required a 2-fold coincidence signal in its photomultiplier arrays, enforced in data analysis. The technique presented here exploits the double photoelectron emission effect observed in some photomultiplier models at vacuum ultraviolet wavelengths. We demonstrate this analysis using an electron recoil calibration dataset and place new constraints on the spin-independent scattering cross section of weakly interacting massive particles (WIMPs) down to 2.5 GeV/c$^2$ WIMP mass using the 2013 LUX dataset. This new technique is promising to enhance light WIMP and astrophysical neutrino searches in next-generation liquid xenon experiments.
Published: 2019
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2. Results of a Search for Sub-GeV Dark Matter Using 2013 LUX Data

Author: Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Boxer, B., Brás, P., Burdin, S., Byram, D., Carmona-Benitez, M. C., Chan, C., Cutter, J. E., Davison, T. J. R., Druszkiewicz, E., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Gwilliam, C., Hall, C. R., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Jahangir, O., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Korolkova, E. V., Kravitz, S., Kudryavtsev, V. A., Lenardo, B. G., Lesko, K. T., Liao, J., Lin, J., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marangou, N., Marzioni, M. F., McKinsey, D. N., Mei, D. -M., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Naylor, A., Nehrkorn, C., Nelson, H. N., Neves, F., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Riffard, Q., Rischbieter, G. R. C., Rhyne, C., Rossiter, P., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Utku, U., Uvarov, S., Velan, V., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Woodward, D., Xu, J., Yazdani, K., and Zhang, C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a Bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5 GeV/c$^2$ using 1.4$\times10^4$ kg$\cdot$day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.
Published: 2018
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3. Search for annual and diurnal rate modulations in the LUX experiment

Author: Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Boxer, B., Brás, P., Burdin, S., Byram, D., Carmona-Benitez, M. C., Chan, C., Cutter, J. E., Davison, T. J. R., Druszkiewicz, E., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Gwilliam, C., Hall, C. R., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Korolkova, E. V., Kravitz, S., Kudryavtsev, V. A., Lenardo, B. G., Lesko, K. T., Liao, J., Lin, J., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marangou, N., Marzioni, M. F., McKinsey, D. N., Mei, D. -M., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Rischbieter, G. R. C., Rhyne, C., Rossiter, P., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Utku, U., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Woodward, D., Xu, J., Yazdani, K., and Zhang, C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: Various dark matter models predict annual and diurnal modulations of dark matter interaction rates in Earth-based experiments as a result of the Earth's motion in the halo. Observation of such features can provide generic evidence for detection of dark matter interactions. This paper reports a search for both annual and diurnal rate modulations in the LUX dark matter experiment using over 20 calendar months of data acquired between 2013 and 2016. This search focuses on electron recoil events at low energies, where leptophilic dark matter interactions are expected to occur and where the DAMA experiment has observed a strong rate modulation for over two decades. By using the innermost volume of the LUX detector and developing robust cuts and corrections, we obtained a stable event rate of 2.3$\pm$0.2~cpd/keV$_{\text{ee}}$/tonne, which is among the lowest in all dark matter experiments. No statistically significant annual modulation was observed in energy windows up to 26~keV$_{\text{ee}}$. Between 2 and 6~keV$_{\text{ee}}$, this analysis demonstrates the most sensitive annual modulation search up to date, with 9.2$\sigma$ tension with the DAMA/LIBRA result. We also report no observation of diurnal modulations above 0.2~cpd/keV$_{\text{ee}}$/tonne amplitude between 2 and 6~keV$_{\text{ee}}$., Comment: 12 pages, 9 figures
Published: 2018
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4. LUX Trigger Efficiency

Author: Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Boxer, B., Brás, P., Burdin, S., Byram, D., Carmona-Benitez, M. C., Chan, C., Cutter, J. E., Davison, T. J. R., Druszkiewicz, E., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Grace, E., Gwilliam, C., Hall, C. R., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Korolkova, E. V., Kravitz, S., Kudryavtsev, V. A., Lenardo, B. G., Lesko, K. T., Liao, J., Lin, J., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marangou, N., Marzioni, M. F., McKinsey, D. N., Mei, D. -M., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Rischbieter, G. R. C., Rhyne, C., Rossiter, P., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Utku, U., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Woodward, D., Xu, J., Yazdani, K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors
Abstract: The Large Underground Xenon experiment (LUX) searches for dark matter using a dual-phase xenon detector. LUX uses a custom-developed trigger system for event selection. In this paper, the trigger efficiency, which is defined as the probability that an event of interest is selected for offline analysis, is studied using raw data obtained from both electron recoil (ER) and nuclear recoil (NR) calibrations. The measured efficiency exceeds 98\% at a pulse area of 90 detected photons, which is well below the WIMP analysis threshold on the S2 pulse area. The efficiency also exceeds 98\% at recoil energies of \mbox{0.2 keV} and above for ER, and \mbox{1.3 keV} and above for NR. The measured trigger efficiency varies between 99\% and 100\% over the fiducial volume of the detector., Comment: 31 pages, 14 figures
Published: 2018
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5. Liquid xenon scintillation measurements and pulse shape discrimination in the LUX dark matter detector

Author: The LUX Collaboration, Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Carmona-Benitez, M. C., Chan, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Druszkiewicz, E., Edwards, B. N., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Hall, C. R., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Lenardo, B. G., Lesko, K. T., Liao, J., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Utku, U., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors
Abstract: Weakly Interacting Massive Particles (WIMPs) are a leading candidate for dark matter and are expected to produce nuclear recoil (NR) events within liquid xenon time-projection chambers. We present a measurement of the scintillation timing characteristics of liquid xenon in the LUX dark matter detector and develop a pulse shape discriminant to be used for particle identification. To accurately measure the timing characteristics, we develop a template-fitting method to reconstruct the detection times of photons. Analyzing calibration data collected during the 2013-16 LUX WIMP search, we provide a new measurement of the singlet-to-triplet scintillation ratio for electron recoils (ER) below 46~keV, and we make a first-ever measurement of the NR singlet-to-triplet ratio at recoil energies below 74~keV. We exploit the difference of the photon time spectra for NR and ER events by using a prompt fraction discrimination parameter, which is optimized using calibration data to have the least number of ER events that occur in a 50\% NR acceptance region. We then demonstrate how this discriminant can be used in conjunction with the charge-to-light discrimination to possibly improve the signal-to-noise ratio for nuclear recoils., Comment: 16 pages, 11 figures
Published: 2018
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6. Calibration, event reconstruction, data analysis and limits calculation for the LUX dark matter experiment

Author: Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors
Abstract: The LUX experiment has performed searches for dark matter particles scattering elastically on xenon nuclei, leading to stringent upper limits on the nuclear scattering cross sections for dark matter. Here, for results derived from ${1.4}\times 10^{4}\;\mathrm{kg\,days}$ of target exposure in 2013, details of the calibration, event-reconstruction, modeling, and statistical tests that underlie the results are presented. Detector performance is characterized, including measured efficiencies, stability of response, position resolution, and discrimination between electron- and nuclear-recoil populations. Models are developed for the drift field, optical properties, background populations, the electron- and nuclear-recoil responses, and the absolute rate of low-energy background events. Innovations in the analysis include in situ measurement of the photomultipliers' response to xenon scintillation photons, verification of fiducial mass with a low-energy internal calibration source, and new empirical models for low-energy signal yield based on large-sample, in situ calibrations.
Published: 2017
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7. Results of a Search for Sub-GeV Dark Matter Using 2013 LUX Data

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Boxer, B, Brás, P, Burdin, S, Byram, D, Carmona-Benitez, MC, Chan, C, Cutter, JE, Davison, TJR, Druszkiewicz, E, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Gwilliam, C, Hall, CR, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Jahangir, O, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Korolkova, EV, Kravitz, S, Kudryavtsev, VA, Lenardo, BG, Lesko, KT, Liao, J, Lin, J, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marangou, N, Marzioni, MF, McKinsey, DN, Mei, D-M, Moongweluwan, M, Morad, JA, Murphy, A St J, Naylor, A, Nehrkorn, C, Nelson, HN, Neves, F, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Riffard, Q, Rischbieter, GRC, Rhyne, C, Rossiter, P, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Utku, U, Uvarov, S, Velan, V, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Woodward, D, Xu, J, Yazdani, K, and Zhang, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, LUX Collaboration, astro-ph.CO, astro-ph.IM, hep-ex, physics.ins-det, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5 GeV/c^{2} using 1.4×10^{4} kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.
Published: 2019

8. Position Reconstruction in LUX

Author: LUX Collaboration, Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Druszkiewicz, E., Edwards, B. N., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Physics - Computational Physics
Abstract: The $(x, y)$ position reconstruction method used in the analysis of the complete exposure of the Large Underground Xenon (LUX) experiment is presented. The algorithm is based on a statistical test that makes use of an iterative method to recover the photomultiplier tube (PMT) light response directly from the calibration data. The light response functions make use of a two dimensional functional form to account for the photons reflected on the inner walls of the detector. To increase the resolution for small pulses, a photon counting technique was employed to describe the response of the PMTs. The reconstruction was assessed with calibration data including ${}^{\mathrm{83m}}$Kr (releasing a total energy of 41.5 keV) and ${}^{3}$H ($\beta^-$ with Q = 18.6 keV) decays, and a deuterium-deuterium (D-D) neutron beam (2.45 MeV). In the horizontal plane, the reconstruction has achieved an $(x, y)$ position uncertainty of $\sigma$= 0.82 cm for events of only 200 electroluminescence photons and $\sigma$ = 0.17 cm for 4,000 electroluminescence photons. Such signals are associated with electron recoils of energies $\sim$0.25 keV and $\sim$10 keV, respectively. The reconstructed position of the smallest events with a single electron emitted from the liquid surface has a horizontal $(x, y)$ uncertainty of 2.13 cm., Comment: 30 pages, 17 figures
Published: 2017
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9. Ultra-Low Energy Calibration of LUX Detector using $^{127}$Xe Electron Capture

Author: LUX Collaboration, Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Druszkiewicz, E., Edwards, B. N., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract: We report an absolute calibration of the ionization yields($\textit{Q$_y$})$ and fluctuations for electronic recoil events in liquid xenon at discrete energies between 186 eV and 33.2 keV. The average electric field applied across the liquid xenon target is 180 V/cm. The data are obtained using low energy $^{127}$Xe electron capture decay events from the 95.0-day first run from LUX (WS2013) in search of Weakly Interacting Massive Particles (WIMPs). The sequence of gamma-ray and X-ray cascades associated with $^{127}$I de-excitations produces clearly identified 2-vertex events in the LUX detector. We observe the K- (binding energy, 33.2 keV), L- (5.2 keV), M- (1.1 keV), and N- (186 eV) shell cascade events and verify that the relative ratio of observed events for each shell agrees with calculations. The N-shell cascade analysis includes single extracted electron (SE) events and represents the lowest-energy electronic recoil $\textit{in situ}$ measurements that have been explored in liquid xenon., Comment: 10 pages, 10 figures, 2 tables
Published: 2017
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10. 3D Modeling of Electric Fields in the LUX Detector

Author: LUX Collaboration, Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Druszkiewicz, E., Edwards, B. N., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Physics - Computational Physics
Abstract: This work details the development of a three-dimensional (3D) electric field model for the LUX detector. The detector took data during two periods of searching for weakly interacting massive particle (WIMP) searches. After the first period completed, a time-varying non-uniform negative charge developed in the polytetrafluoroethylene (PTFE) panels that define the radial boundary of the detector's active volume. This caused electric field variations in the detector in time, depth and azimuth, generating an electrostatic radially-inward force on electrons on their way upward to the liquid surface. To map this behavior, 3D electric field maps of the detector's active volume were built on a monthly basis. This was done by fitting a model built in COMSOL Multiphysics to the uniformly distributed calibration data that were collected on a regular basis. The modeled average PTFE charge density increased over the course of the exposure from -3.6 to $-5.5~\mu$C/m$^2$. From our studies, we deduce that the electric field magnitude varied while the mean value of the field of $\sim200$~V/cm remained constant throughout the exposure. As a result of this work the varying electric fields and their impact on event reconstruction and discrimination were successfully modeled.
Published: 2017
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11. $^{83\textrm{m}}$Kr calibration of the 2013 LUX dark matter search

Author: LUX Collaboration, Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Druszkiewicz, E., Edwards, B. N., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Genovesi, J., Ghag, C., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors
Abstract: LUX was the first dark matter experiment to use a $^{83\textrm{m}}$Kr calibration source. In this paper we describe the source preparation and injection. We also present several $^{83\textrm{m}}$Kr calibration applications in the context of the 2013 LUX exposure, including the measurement of temporal and spatial variation in scintillation and charge signal amplitudes, and several methods to understand the electric field within the time projection chamber.
Published: 2017
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12. Limits on spin-dependent WIMP-nucleon cross section obtained from the complete LUX exposure

Author: LUX Collaboration, Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fallon, S. R., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg-year exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% CL upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of $\sigma_n$ = 1.6$\times 10^{-41}$ cm$^{2}$ ($\sigma_p$ = 5$\times 10^{-40}$ cm$^{2}$) at 35 GeV$c^{-2}$, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date., Comment: 7 pages, 3 figures, version accepted by PRL
Published: 2017
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13. First Searches for Axions and Axion-Like Particles with the LUX Experiment

Author: Akerib, D. S., Alsum, S., Aquino, C., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fallon, S. R., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Phenomenology
Abstract: The first searches for axions and axion-like particles with the Large Underground Xenon (LUX) experiment are presented. Under the assumption of an axio-electric interaction in xenon, the coupling constant between axions and electrons, gAe is tested, using data collected in 2013 with an exposure totalling 95 live-days $\times$ 118 kg. A double-sided, profile likelihood ratio statistic test excludes gAe larger than 3.5 $\times$ 10$^{-12}$ (90% C.L.) for solar axions. Assuming the DFSZ theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12 eV/c$^{2}$, while for the KSVZ description masses above 36.6 eV/c$^{2}$ are excluded. For galactic axion-like particles, values of gAe larger than 4.2 $\times$ 10$^{-13}$ are excluded for particle masses in the range 1-16 keV/c$^{2}$. These are the most stringent constraints to date for these interactions.
Published: 2017
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14. LUX trigger efficiency

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, B. Boxer, Brás, P, S. Burdin, Byram, D, Carmona-Benitez, MC, Chan, C, Cutter, JE, Davison, TJR, Druszkiewicz, E, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, E. Grace, C. Gwilliam, Hall, CR, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, E.V. Korolkova, S. Kravitz, V.A. Kudryavtsev, Lenardo, BG, Lesko, KT, Liao, J, J. Lin, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marangou, N, Marzioni, MF, McKinsey, DN, Mei, DM, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, G. Rischbieter, Rhyne, C, P. Rossiter, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Utku, U, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, D. Woodward, Xu, J, Yazdani, K, and Zhang, C
Subjects: Trigger efficiency, Dark matter detectors, WIMPs, Liquid xenon, physics.ins-det, Nuclear & Particles Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Other Physical Sciences
Abstract: The Large Underground Xenon experiment (LUX) searches for dark matter using a dual-phase xenon detector. LUX uses a custom-developed trigger system for event selection. In this paper, the trigger efficiency, which is defined as the probability that an event of interest is selected for offline analysis, is studied using raw data obtained from both electron recoil (ER) and nuclear recoil (NR) calibrations. The measured efficiency exceeds 98% at a pulse area of 90 detected photons, which is well below the WIMP analysis threshold on the S2 pulse area. The efficiency also exceeds 98% at recoil energies of 0.2 keV and above for ER, and 1.3 keV and above for NR. The measured trigger efficiency varies between 99% and 100% over the fiducial volume of the detector.
Published: 2018

15. Search for annual and diurnal rate modulations in the LUX experiment

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Boxer, B, Brás, P, Burdin, S, Byram, D, Carmona-Benitez, MC, Chan, C, Cutter, JE, Davison, TJR, Druszkiewicz, E, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Gwilliam, C, Hall, CR, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Korolkova, EV, Kravitz, S, Kudryavtsev, VA, Lenardo, BG, Lesko, KT, Liao, J, Lin, J, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marangou, N, Marzioni, MF, McKinsey, DN, Mei, DM, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rischbieter, GRC, Rhyne, C, Rossiter, P, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Utku, U, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Woodward, D, Xu, J, Yazdani, K, and Zhang, C
Subjects: astro-ph.CO, astro-ph.IM, hep-ex, physics.ins-det
Abstract: Various dark matter models predict annual and diurnal modulations of dark matter interaction rates in Earth-based experiments as a result of the Earth's motion in the halo. Observation of such features can provide generic evidence for detection of dark matter interactions. This paper reports a search for both annual and diurnal rate modulations in the LUX dark matter experiment using over 20 calendar months of data acquired between 2013 and 2016. This search focuses on electron recoil events at low energies, where leptophilic dark matter interactions are expected to occur and where the DAMA experiment has observed a strong rate modulation for over two decades. By using the innermost volume of the LUX detector and developing robust cuts and corrections, we obtained a stable event rate of 2.3±0.2 cpd/keVee/tonne, which is among the lowest in all dark matter experiments. No statistically significant annual modulation was observed in energy windows up to 26 keVee. Between 2 and 6 keVee, this analysis demonstrates the most sensitive annual modulation search up to date, with 9.2σ tension with the DAMA/LIBRA result. We also report no observation of diurnal modulations above 0.2 cpd/keVee/tonne amplitude between 2 and 6 keVee.
Published: 2018

16. Liquid xenon scintillation measurements and pulse shape discrimination in the LUX dark matter detector

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Lenardo, BG, Lesko, KT, Liao, J, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Utku, U, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: physics.ins-det
Abstract: Weakly interacting massive particles (WIMPs) are a leading candidate for dark matter and are expected to produce nuclear recoil (NR) events within liquid xenon time-projection chambers. We present a measurement of the scintillation timing characteristics of liquid xenon in the LUX dark matter detector and develop a pulse shape discriminant to be used for particle identification. To accurately measure the timing characteristics, we develop a template-fitting method to reconstruct the detection times of photons. Analyzing calibration data collected during the 2013-2016 LUX WIMP search, we provide a new measurement of the singlet-to-triplet scintillation ratio for electron recoils (ER) below 46 keV, and we make, to our knowledge, a first-ever measurement of the NR singlet-to-triplet ratio at recoil energies below 74 keV. We exploit the difference of the photon time spectra for NR and ER events by using a prompt fraction discrimination parameter, which is optimized using calibration data to have the least number of ER events that occur in a 50% NR acceptance region. We then demonstrate how this discriminant can be used in conjunction with the charge-to-light discrimination to possibly improve the signal-to-noise ratio for nuclear recoils.
Published: 2018

17. Calibration, event reconstruction, data analysis, and limit calculation for the LUX dark matter experiment

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, St. J. Murphy, A, Nehrkorn, C, Nelson, HN, Neves, F, O’Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, physics.ins-det
Abstract: The LUX experiment has performed searches for dark-matter particles scattering elastically on xenon nuclei, leading to stringent upper limits on the nuclear scattering cross sections for dark matter. Here, for results derived from 1.4×104 kg days of target exposure in 2013, details of the calibration, event-reconstruction, modeling, and statistical tests that underlie the results are presented. Detector performance is characterized, including measured efficiencies, stability of response, position resolution, and discrimination between electron- and nuclear-recoil populations. Models are developed for the drift field, optical properties, background populations, the electron- and nuclear-recoil responses, and the absolute rate of low-energy background events. Innovations in the analysis include in situ measurement of the photomultipliers' response to xenon scintillation photons, verification of fiducial mass with a low-energy internal calibration source, and new empirical models for low-energy signal yield based on large-sample, in situ calibrations.
Published: 2018

18. Position reconstruction in LUX

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Dark Matter detectors, Liquid detectors, Charge transport, multiplication and electroluminescence in rare gases and liquids, Detector modelling and simulations I, physics.ins-det, hep-ex, physics.comp-ph, Engineering, Nuclear & Particles Physics, Physical sciences
Abstract: The (x, y) position reconstruction method used in the analysis of the complete exposure of the Large Underground Xenon (LUX) experiment is presented. The algorithm is based on a statistical test that makes use of an iterative method to recover the photomultiplier tube (PMT) light response directly from the calibration data. The light response functions make use of a two dimensional functional form to account for the photons reflected on the inner walls of the detector. To increase the resolution for small pulses, a photon counting technique was employed to describe the response of the PMTs. The reconstruction was assessed with calibration data including 83mKr (releasing a total energy of 41.5 keV) and 3H (andbeta;- with Q = 18.6 keV) decays, and a deuterium-deuterium (D-D) neutron beam (2.45 MeV) . Within the detector's fiducial volume, the reconstruction has achieved an (x, y) position uncertainty of andsigma; = 0.82 cm and andsigma; = 0.17 cm for events of only 200 and 4,000 detected electroluminescence photons respectively. Such signals are associated with electron recoils of energies andsim;0.25 keV and andsim;10 keV, respectively. The reconstructed position of the smallest events with a single electron emitted from the liquid surface (22 detected photons) has a horizontal (x, y) uncertainty of 2.13 cm.
Published: 2018

19. Chromatographic separation of radioactive noble gases from xenon

Author: Akerib, DS, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Bramante, R, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chiller, AA, Chiller, C, Coffey, T, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gibson, KR, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Ihm, M, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, Nehrkorn, C, Nelson, HN, Neves, F, O’Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Pech, K, Phelps, P, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, W, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Yazdani, K, Young, SK, and Zhang, C
Subjects: Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Xenon, Krypton, Adsorption, Chromatography, Gas Separation, Dark Matter, physics.ins-det, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Astronomical sciences, Particle and high energy physics
Abstract: The Large Underground Xenon (LUX) experiment operates at the Sanford Underground Research Facility to detect nuclear recoils from the hypothetical Weakly Interacting Massive Particles (WIMPs) on a liquid xenon target. Liquid xenon typically contains trace amounts of the noble radioactive isotopes 85Kr and 39Ar that are not removed by the in situ gas purification system. The decays of these isotopes at concentrations typical of research-grade xenon would be a dominant background for a WIMP search experiment. To remove these impurities from the liquid xenon, a chromatographic separation system based on adsorption on activated charcoal was built. 400 kg of xenon was processed, reducing the average concentration of krypton from 130 ppb to 3.5 ppt as measured by a cold-trap assisted mass spectroscopy system. A 50 kg batch spiked to 0.001 g/g of krypton was processed twice and reduced to an upper limit of 0.2 ppt.
Published: 2018

20. Ultralow energy calibration of LUX detector using Xe 127 electron capture

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: physics.ins-det, astro-ph.IM, hep-ex
Abstract: We report an absolute calibration of the ionization yields (Qy) and fluctuations for electronic recoil events in liquid xenon at discrete energies between 186 eV and 33.2 keV. The average electric field applied across the liquid xenon target is 180 V/cm. The data are obtained using low energy Xe127 electron capture decay events from the 95.0-day first run from LUX (WS2013) in search of weakly interacting massive particles. The sequence of gamma-ray and x-ray cascades associated with I127 deexcitations produces clearly identified two-vertex events in the LUX detector. We observe the K-(binding energy, 33.2 keV), L-(5.2 keV), M-(1.1 keV), and N-(186 eV) shell cascade events and verify that the relative ratio of observed events for each shell agrees with calculations. The N-shell cascade analysis includes single extracted electron (SE) events and represents the lowest-energy electronic recoil in situ measurements that have been explored in liquid xenon.
Published: 2017

21. Kr 83 m calibration of the 2013 LUX dark matter search

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: physics.ins-det
Abstract: LUX was the first dark matter experiment to use a Kr83m calibration source. In this paper, we describe the source preparation and injection. We also present several Kr83m calibration applications in the context of the 2013 LUX exposure, including the measurement of temporal and spatial variation in scintillation and charge signal amplitudes, and several methods to understand the electric field within the time projection chamber.
Published: 2017

22. Kr83m calibration of the 2013 LUX dark matter search

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, St. J. Murphy, A, Nehrkorn, C, Nelson, HN, Neves, F, O’Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, physics.ins-det
Abstract: LUX was the first dark matter experiment to use a Kr83m calibration source. In this paper, we describe the source preparation and injection. We also present several Kr83m calibration applications in the context of the 2013 LUX exposure, including the measurement of temporal and spatial variation in scintillation and charge signal amplitudes, and several methods to understand the electric field within the time projection chamber.
Published: 2017

23. Ultralow energy calibration of LUX detector using Xe127 electron capture

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, St. J. Murphy, A, Nehrkorn, C, Nelson, HN, Neves, F, O’Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, physics.ins-det, astro-ph.IM, hep-ex
Abstract: We report an absolute calibration of the ionization yields (Qy) and fluctuations for electronic recoil events in liquid xenon at discrete energies between 186 eV and 33.2 keV. The average electric field applied across the liquid xenon target is 180 V/cm. The data are obtained using low energy Xe127 electron capture decay events from the 95.0-day first run from LUX (WS2013) in search of weakly interacting massive particles. The sequence of gamma-ray and x-ray cascades associated with I127 deexcitations produces clearly identified two-vertex events in the LUX detector. We observe the K-(binding energy, 33.2 keV), L-(5.2 keV), M-(1.1 keV), and N-(186 eV) shell cascade events and verify that the relative ratio of observed events for each shell agrees with calculations. The N-shell cascade analysis includes single extracted electron (SE) events and represents the lowest-energy electronic recoil in situ measurements that have been explored in liquid xenon.
Published: 2017

24. Signal yields, energy resolution, and recombination fluctuations in liquid xenon

Author: Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Bramante, R., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Ihm, M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. -M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Phelps, P., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract: This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon re- combination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2-16 keV with $^3$H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data., Comment: 11 pages, 12 figures, 3 tables
Published: 2016
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25. Results from a search for dark matter in the complete LUX exposure

Author: Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Bramante, R., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Ihm, M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O`Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Phelps, P., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35e4 kg-day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV/c^2, WIMP-nucleon spin-independent cross sections above 2.2e-46 cm^2 are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1e-46 cm^2 at 50 GeV/c^2., Comment: This version includes a combined analysis with previously published LUX results, and matches the version published in PRL
Published: 2016
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26. Low-energy (0.7-74 keV) nuclear recoil calibration of the LUX dark matter experiment using D-D neutron scattering kinematics

Author: LUX Collaboration, Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Bradley, A., Bramante, R., Brás, P., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chapman, J. J., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., de Viveiros, L., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Ihm, M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Malling, D. C., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pangilinan, M., Pease, E. K., Phelps, P., Reichhart, L., Rhyne, C. A., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Xu, J., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract: The Large Underground Xenon (LUX) experiment is a dual-phase liquid xenon time projection chamber (TPC) operating at the Sanford Underground Research Facility in Lead, South Dakota. A calibration of nuclear recoils in liquid xenon was performed $\textit{in situ}$ in the LUX detector using a collimated beam of mono-energetic 2.45 MeV neutrons produced by a deuterium-deuterium (D-D) fusion source. The nuclear recoil energy from the first neutron scatter in the TPC was reconstructed using the measured scattering angle defined by double-scatter neutron events within the active xenon volume. We measured the absolute charge ($Q_{y}$) and light ($L_{y}$) yields at an average electric field of 180 V/cm for nuclear recoil energies spanning 0.7 to 74 keV and 1.1 to 74 keV, respectively. This calibration of the nuclear recoil signal yields will permit the further refinement of liquid xenon nuclear recoil signal models and, importantly for dark matter searches, clearly demonstrates measured ionization and scintillation signals in this medium at recoil energies down to $\mathcal{O}$(1 keV)., Comment: 24 pages, 15 figures, 6 tables
Published: 2016

27. Chromatographic separation of radioactive noble gases from xenon

Author: LUX Collaboration, Akerib, D. S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Bramante, R., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chiller, A. A., Chiller, C., Coffey, T., Currie, A., Cutter, J. E., Davison, T. J. R., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Ihm, M., Jacobsen, R. G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. -M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Pech, K., Phelps, P., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Physics - Instrumentation and Detectors
Abstract: The Large Underground Xenon (LUX) experiment operates at the Sanford Underground Research Facility to detect nuclear recoils from the hypothetical Weakly Interacting Massive Particles (WIMPs) on a liquid xenon target. Liquid xenon typically contains trace amounts of the noble radioactive isotopes $^{85}$Kr and $^{39}$Ar that are not removed by the in situ gas purification system. The decays of these isotopes at concentrations typical of research-grade xenon would be a dominant background for a WIMP search exmperiment. To remove these impurities from the liquid xenon, a chromatographic separation system based on adsorption on activated charcoal was built. 400 kg of xenon was processed, reducing the average concentration of krypton from 130 ppb to 3.5 ppt as measured by a cold-trap assisted mass spectroscopy system. A 50 kg batch spiked to 0.001 g/g of krypton was processed twice and reduced to an upper limit of 0.2 ppt., Comment: Accepted in Astropart. Phys
Published: 2016
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28. Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment

Author: LUX Collaboration, Akerib, D. S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Bradley, A., Bramante, R., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chapman, J. J., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., de Viveiros, L., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Ihm, M., Jacobsen, R. G., Ji, W., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Malling, D. C., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Ott, R. A., Palladino, K. J., Pangilinan, M., Pease, E. K., Phelps, P., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract: We present the first experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of $1.4~\times~10^{4}~\text{kg}\cdot~\text{days}$ of fiducial exposure allows 90% CL upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of $\sigma_n~=~9.4~\times~10^{-41}~\text{cm}^2$ ($\sigma_p~=~2.9~\times~10^{-39}~\text{cm}^2$) at 33 GeV/c$^2$. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date., Comment: 6 pages, 2 figures
Published: 2016
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29. Improved Limits on Scattering of Weakly Interacting Massive Particles from Reanalysis of 2013 LUX data

Author: LUX Collaboration, Akerib, D. S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Bradley, A., Bramante, R., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chapman, J. J., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., de Viveiros, L., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Ihm, M., Jacobsen, R. G., Ji, W., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Malling, D. C., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Nehrkorn, C., Nelson, H. N., Neves, F., O`Sullivan, K., Oliver-Mallory, K. C., Ott, R. A., Palladino, K. J., Pangilinan, M., Pease, E. K., Phelps, P., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Yazdani, K., Young, S. K., and Zhang, C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including $1.4\times10^{4}\;\mathrm{kg\; day}$ of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium $\beta$ source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4 $\mathrm{GeV}\,c^{-2}$, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% C.L. upper limit has a minimum of 0.6 zb at 33 $\mathrm{GeV}\,c^{-2}$ WIMP mass., Comment: Accepted by Phys. Rev. Lett
Published: 2015
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30. 3D modeling of electric fields in the LUX detector

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: Analysis and statistical methods, Detector modelling and simulations II, Noble liquid detectors, Dark Matter detectors, physics.ins-det, hep-ex, physics.comp-ph, Nuclear & Particles Physics, Physical Sciences, Engineering
Abstract: This work details the development of a three-dimensional (3D) electric field model for the LUX detector. The detector took data to search for weakly interacting massive particles (WIMPs) during two periods. After the first period completed, a time-varying non-uniform negative charge developed in the polytetrafluoroethylene (PTFE) panels that define the radial boundary of the detector's active volume. This caused electric field variations in the detector in time, depth and azimuth, generating an electrostatic radially-inward force on electrons on their way upward to the liquid surface. To map this behavior, 3D electric field maps of the detector's active volume were generated on a monthly basis. This was done by fitting a model built in COMSOL Multiphysics to the uniformly distributed calibration data that were collected on a regular basis. The modeled average PTFE charge density increased over the course of the exposure from -3.6 to -5.5 μC/m2. From our studies, we deduce that the electric field magnitude varied locally while the mean value of the field of ∼200 V/cm remained constant throughout the exposure. As a result of this work the varying electric fields and their impact on event reconstruction and discrimination were successfully modeled.
Published: 2017

31. First Searches for Axions and Axionlike Particles with the LUX Experiment

Author: Akerib, DS, Alsum, S, Aquino, C, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chiller, AA, Chiller, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fallon, SR, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gibson, KR, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, A St J, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, and Young, SK
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, LUX Collaboration, astro-ph.CO, hep-ph, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118 kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12 eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6 eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16 keV/c^{2}. These are the most stringent constraints to date for these interactions.
Published: 2017

32. Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chiller, AA, Chiller, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fallon, SR, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, A St J, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, LUX Collaboration, astro-ph.CO, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41} cm^{2} (σ_{p}=5×10^{-40} cm^{2}) at 35 GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.
Published: 2017

33. Signal yields, energy resolution, and recombination fluctuations in liquid xenon

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Bramante, R, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chiller, AA, Chiller, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gibson, KR, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Ihm, M, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Phelps, P, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, and Young, SK
Subjects: physics.ins-det, hep-ex
Abstract: This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon recombination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2 and 16 keV with H3. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.
Published: 2017

34. Results from a Search for Dark Matter in the Complete LUX Exposure

Author: Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Bramante, R, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chiller, AA, Chiller, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gibson, KR, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Ihm, M, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, A St J, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Phelps, P, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, and Young, SK
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, LUX Collaboration, astro-ph.CO, astro-ph.IM, hep-ex, physics.ins-det, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×10^{4} kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV c^{-2}, WIMP-nucleon spin-independent cross sections above 2.2×10^{-46} cm^{2} are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10^{-46} cm^{2} at 50 GeV c^{-2}.
Published: 2017

35. Improved Limits on Scattering of Weakly Interacting Massive Particles from Reanalysis of 2013 LUX Data

Author: Akerib, DS, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Bradley, A, Bramante, R, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chapman, JJ, Chiller, AA, Chiller, C, Currie, A, Cutter, JE, Davison, TJR, de Viveiros, L, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gibson, KR, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Ihm, M, Jacobsen, RG, Ji, W, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Malling, DC, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, A St J, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Ott, RA, Palladino, KJ, Pangilinan, M, Pease, EK, Phelps, P, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, W, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Yazdani, K, and Young, SK
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, LUX Collaboration, astro-ph.CO, astro-ph.IM, hep-ex, physics.ins-det, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including 1.4×10^{4} kg day of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium β source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4 GeV c^{-2}, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% C.L. upper limit has a minimum of 0.6 zb at 33 GeV c^{-2} WIMP mass.
Published: 2016

36. Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment

Author: Akerib, DS, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Bradley, A, Bramante, R, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chapman, JJ, Chiller, AA, Chiller, C, Currie, A, Cutter, JE, Davison, TJR, de Viveiros, L, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gibson, KR, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Ihm, M, Jacobsen, RG, Ji, W, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Malling, DC, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, A St J, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Ott, RA, Palladino, KJ, Pangilinan, M, Pease, EK, Phelps, P, Reichhart, L, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, W, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Yazdani, K, and Young, SK
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, LUX Collaboration, hep-ex, hep-ph, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4×10^{4} kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=9.4×10^{-41} cm^{2} (σ_{p}=2.9×10^{-39} cm^{2}) at 33 GeV/c^{2}. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.
Published: 2016

37. Estimation of Generalized Impact Fraction and Population Attributable Fraction of Hypertension Based on JNC-IV and 2017 ACC/AHA Guidelines for Cardiovascular Diseases Using Parametric G-Formula: Tehran Lipid and Glucose Study (TLGS)

Author: Saatchi M, Mansournia MA, Khalili D, Daroudi R, and Yazdani K
Subjects: generalized impact fraction (gif), population attributable fraction (paf), hypertension, cardiovascular diseases, 2017 acc/aha guidelines, parametric g-formula, Public aspects of medicine, RA1-1270
Abstract: Mohammad Saatchi,1 Mohammad Ali Mansournia,1 Davood Khalili,2 Rajabali Daroudi,3 Kamran Yazdani1 1Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; 2Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 3Department of Health Management and Economics, School of Public Health, Tehran University of Medical Sciences, Tehran, IranCorrespondence: Kamran YazdaniDepartment of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, P.O. Box 644614155, Tehran, IranTel +98 912 297 9264Email kyazdani@tums.ac.irPurpose: An area of interest to health policymakers is the effect of interventions aimed at risk factors on decreasing the number of new cardiovascular disease (CVD) cases. The aim of this study was to estimate the generalized impact fraction (GIF) and population attributable fraction (PAF) of hypertension (HTN) for CVD in Tehran.Patients and Methods: In this population-based cohort study, 8071 participants aged ≥ 30 years were followed for a median of 16 years. A survival model was used to estimate the 10- and 18-year risk of CVD. JNC-IV and 2017 ACC/AHA guidelines were used to categorize blood pressure (BP). PAF and GIF were estimated in different scenarios using the parametric G-formula.Results: Of 7378 participants included in analyses, 22.7% and 52.3% were classified as hypertensive according to the JNC-IV and 2017 ACC/AHA guidelines, respectively. According to the 2017 ACC/AHA, the 10-year risk of CVD was 5.1% (4.3– 6.0%), 8.9% (6.7– 12.0%), and 7.1% (6.1– 8.4%) for normal BP, elevated BP, and stage 1 HTN, respectively, and 20.8% (18.8– 23.0%) for stage 2 of the 2017 ACC/AHA and JNC-IV. The PAF of stage 2 vs stage 1 and vs normal BP for CVD was 17.4% (11.5– 21.8%) and 20.4% (14.6– 26.4%), respectively. The GIF of 30% reduction in the prevalence of stage 2 HTN to stage 1 and to normal BP for CVD was 5.1% (3.4– 6.6%) and 6.1% (4.4– 8.0%), respectively. Based on JNC-IV, the PAF and GIF of 30% for CVD were 17.8% (12.7– 22.9%) and 5.4% (4.0– 6.9%), respectively.Conclusion: By reducing the prevalence of HTN by 30%, a remarkable number of new CVD cases would be prevented. In an Iranian population, the comparison of HTN cases with normal BP showed no association between stage 1 HTN and CVD, whereas elevated BP was a significant risk factor for the incidence of CVD.Keywords: generalized impact fraction, GIF, population attributable fraction, PAF, hypertension, cardiovascular diseases, 2017 ACC/AHA guidelines, parametric G-formula
Published: 2020

38. Chromatographic separation of radioactive noble gases from xenon

Author: Akerib, D.S., Araújo, H.M., Bai, X., Bailey, A.J., Balajthy, J., Beltrame, P., Bernard, E.P., Bernstein, A., Biesiadzinski, T.P., Boulton, E.M., Bramante, R., Cahn, S.B., Carmona-Benitez, M.C., Chan, C., Chiller, A.A., Chiller, C., Coffey, T., Currie, A., Cutter, J.E., Davison, T.J.R., Dobi, A., Dobson, J.E.Y., Druszkiewicz, E., Edwards, B.N., Faham, C.H., Fiorucci, S., Gaitskell, R.J., Gehman, V.M., Ghag, C., Gibson, K.R., Gilchriese, M.G.D., Hall, C.R., Hanhardt, M., Haselschwardt, S.J., Hertel, S.A., Hogan, D.P., Horn, M., Huang, D.Q., Ignarra, C.M., Ihm, M., Jacobsen, R.G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N.A., Lee, C., Lenardo, B.G., Lesko, K.T., Lindote, A., Lopes, M.I., Manalaysay, A., Mannino, R.L., Marzioni, M.F., McKinsey, D.N., Mei, D.-M., Mock, J., Moongweluwan, M., Morad, J.A., Murphy, A.St.J., Nehrkorn, C., Nelson, H.N., Neves, F., O’Sullivan, K., Oliver-Mallory, K.C., Palladino, K.J., Pease, E.K., Pech, K., Phelps, P., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T.A., Silva, C., Solovov, V.N., Sorensen, P., Stephenson, S., Sumner, T.J., Szydagis, M., Taylor, D.J., Taylor, W., Tennyson, B.P., Terman, P.A., Tiedt, D.R., To, W.H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J.R., Webb, R.C., White, J.T., Whitis, T.J., Witherell, M.S., Wolfs, F.L.H., Yazdani, K., Young, S.K., and Zhang, C.
Published: 2018
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39. Extending light WIMP searches to single scintillation photons in LUX

Author: Akerib, D. S., Alsum, S., Ara��jo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Baxter, A., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Boxer, B., Br��s, P., Burdin, S., Byram, D., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., de Viveiros, L., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fallon, S. R., Fan, A., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Genovesi, J., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Grace, E., Gwilliam, C., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Jacobsen, R. G., Jahangir, O., Ji, W., Kamdin, K., Kazka, K., Khaitan, D., Knoche, R., Korolkova, E. V., Kravitz, S., Kudryavtsev, V. A., Larsen, N. A., Leason, E., Lee, C., Lenardo, B. G., Lesko, K. T., Levy, C., Liao, J., Lin, J., Lindote, A., Lopes, M. I., L��pez-Paredes, B., Manalaysay, A., Mannino, R. L., Marangou, N., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, A. St. J., Naylor, A., Nehrkorn, C., Nelson, H. N., Neves, F., Nilima, A., O'Sullivan, K., Oliver-Mallory, K. C., Palladino, K. J., Pease, E. K., Reichhart, L., Riffard, Q., Rischbieter, G. R. C., Rossiter, P., Shaw, S., Shutt, T. A., Silva, C., Solmaz, M., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, R., Taylor, W. C., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Utku, U., Uvarov, S., Vacheret, A., Velan, V., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Woodward, D., Xu, J., Yazdani, K., Young, S. K., Zhang, C., and Science and Technology Facilities Council (STFC)
Subjects: BACKGROUNDS, Photomultiplier, Physics - Instrumentation and Detectors, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Photon, Physics::Instrumentation and Detectors, Dark matter, FOS: Physical sciences, chemistry.chemical_element, Astronomy & Astrophysics, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Physics, Particles & Fields, Nuclear physics, High Energy Physics - Experiment (hep-ex), XENON, Xenon, WIMP, 0103 physical sciences, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), physics.ins-det, Physics, Scintillation, Science & Technology, hep-ex, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Instrumentation and Detectors (physics.ins-det), chemistry, Weakly interacting massive particles, Physical Sciences, astro-ph.CO, Neutrino, Astrophysics - Instrumentation and Methods for Astrophysics, EMISSION, Astrophysics - Cosmology and Nongalactic Astrophysics, astro-ph.IM
Abstract: We present a novel analysis technique for liquid xenon time projection chambers that allows for a lower threshold by relying on events with a prompt scintillation signal consisting of single detected photons. The energy threshold of the LUX dark matter experiment is primarily determined by the smallest scintillation response detectable, which previously required a twofold coincidence signal in its photomultiplier arrays, enforced in data analysis. The technique presented here exploits the double photoelectron emission effect observed in some photomultiplier models at vacuum ultraviolet wavelengths. We demonstrate this analysis using an electron recoil calibration dataset and place new constraints on the spin-independent scattering cross section of weakly interacting massive particles (WIMPs) down to 2.5 GeV / c 2 WIMP mass using the 2013 LUX dataset. This new technique is promising to enhance light WIMP and astrophysical neutrino searches in next-generation liquid xenon experiments.
Published: 2020

40. A search for annual and diurnal rate modulations in the LUX experiment

Author: Akerib, D.S., Alsum, S., Araújo, H.M., Bai, X., Balajthy, J., Beltrame, P., Bernard, E.P., Bernstein, A., Biesiadzinski, T.P., Boulton, E.M., Brás, P., Burdin, S., Byram, D., Carmona-Benitez, M.C., Chan, C., Cutter, J.E., Davison, T.J.R., Druszkiewicz, E., Fallon, S.R., Fan, A., Fiorucci, S., Gaitskell, R.J., Genovesi, J., Ghag, C., Gilchriese, M.G.D., Gwilliam, C., Hall, C.R., Haselschwardt, S.J., Hertel, S.A., Hogan, D.P., Horn, M., Huang, D.Q., Ignarra, C.M., Jacobsen, R.G., Ji, W., Kamdin, K., Kazkaz, K., Khaitan, D., Knoche, L., Korolkova, E.V., Kravitz, S., Kudryavtsev, V.A., Lenardo, B.G., Lesko, K.T., Liao, J., Lindote, A., Lopes, M.I., Manalaysay, A., Mannino, R.L., Marangou, N., Marzioni, M.F., McKinsey, D.N., Mei, D.-M., Moongweluwan, M., Morad, J.A., Murphy, A.S.J., Nehrkorn, C., Nelson, H.N., Neves, F., Oliver-Mallory, K.C., Palladino, K.J., Pease, E.K., Rhyne, C., Rischbieter, G.R.C., Rossiter, P., Shaw, S., Shutt, T.A., Silva, C., Solmaz, M., Solovov, V.N., Sorensen, P., Sumner, T.J., Szydagis, M., Taylor, D.J., Taylor, W.C., Tennyson, B.P., Terman, P.A., Tiedt, D.R., To, W.H., Tripathi, M., Tvrznikova, L., Utku, U., Uvarov, S., Velan, V., Verbus, J.R., Webb, R.C., White, J.T., Whitis, T.J., Witherell, M.S., Wolfs, F.L.H., Woodward, D., Xu, J., Yazdani, K., and Zhang, C.
Abstract: Various dark matter models predict annual and diurnal modulations of dark matter interaction rates in Earth-based experiments as a result of the Earth’s motion in the halo. Observation of such features can provide generic evidence for detection of dark matter interactions. This paper reports a search for both annual and diurnal rate modulations in the LUX dark matter experiment using over 20 calendar months of data acquired between 2013 and 2016. This search focuses on electron recoil events at low energies, where leptophilic dark matter interactions are expected to occur and where the DAMA experiment has observed a strong rate modulation for over two decades. By using the innermost volume of the LUX detector and developing robust cuts and corrections, we obtained a stable event rate of 2.3±0.2 cpd/keVee/tonne, which is among the lowest in all dark matter experiments. No statistically significant annual modulation was observed in energy windows up to 26 keVee. Between 2 and 6 keVee, this analysis demonstrates the most sensitive annual modulation search up to date, with 9.2σ tension with the DAMA/LIBRA result. We also report no observation of diurnal modulations above 0.2 cpd/keVee/tonne amplitude between 2 and 6 keVee.
Published: 2018

41. Kr-83m calibration of the 2013 LUX dark matter search

Author: Akerib, DS, Alsum, S, Araujo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Bras, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, D-M, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, Zhang, C, and Collaboration, LUX
Subjects: physics.ins-det
Abstract: LUX was the first dark matter experiment to use a $^{83\textrm{m}}$Kr calibration source. In this paper we describe the source preparation and injection. We also present several $^{83\textrm{m}}$Kr calibration applications in the context of the 2013 LUX exposure, including the measurement of temporal and spatial variation in scintillation and charge signal amplitudes, and several methods to understand the electric field within the time projection chamber.
Published: 2017

42. Knowledge translation: a model for research utilization

Author: Sadighi J, Majdzadeh R, Nedjat S, Fotouhi A, Shahidzade A, Gholarni J, Yonesian M, Rashidian A, Mesgarpour B, Eternadi A, and Yazdani K
Subjects: knowledge translation, research utilization, university, innovation, Medicine, Medicine (General), R5-920
Abstract: Objective(s): The present study was aimed to design a knowledge transfer model that would provide a conceptual framework for linking the different components of a knowledge translation cycle. Such a theoretical model will enable us to organize and evaluate the current situation and design further studies on the transfer of research generated knowledge. Methods: This research, performed in 2006- 7 in Tehran University of Medical Sciences, utilized two distinct methodologies: the first part was a narrative review with the goal of identifying the existing knowledge transfer models; the second part included focus group discussions to find out the views and opinions of researchers and decision-makers concerning the factors that promote or hinder knowledge translation within the health system. Results: The two studies have provided the input for designing a "Knowledge Translation Cycle" with five domains: Knowledge Creation, Knowledge Transfer, Research Utilization, Question Transfer, and the Context of University. Within each domain, the model includes two components (with the exception of the university context). Conclusion: This model offers a theoretical basis for identifying the basic requirements and the linking mechanisms for the translation of knowledge.
Published: 2008

43. An algorithm of smoking stages assessment in adolescents: A validation study using the latent class analysis model

Author: Mohammadpoorasl, A., Nedjat, S., Yazdani, K., Fakhari, A., Rahimi Foroushani, A., and Akbar Fotouhi
Subjects: validity, reliability, lcsh:R, latent class analysis, lcsh:Medicine, Original Article, smoking stages, Adolescence
Abstract: Background: Notwithstanding the importance of smoking stages evaluation in adolescents, there is not an appropriate instrument for its measurement. This study aims to introduce an appropriate instrument for measurement of smoking stages in adolescents and to examine its validity using latent class analysis (LCA) model. Methods: We designed an algorithm to measure the smoking stages. The relevancy and clarity of the algorithm was examined by experts and lay experts. We assessed the reliability of our algorithm using test-retest method. Moreover, using the LCA, we studied the validity of the stages measured by the designed algorithm in 4903 students (ages 14-19), who were randomly selected from grade 10 high school students in Tabriz (North-West of Iran). Results: The algorithm content validity indicates high relevancy and clarity percentages. Intra-class correlation of 0.929 was found in the assessment of the reliability of smoking stages (9 stages) in 154 students within a two-week interval. The LCA model revealed nine interpretable classes (G 2 = 0.051, df = 1, P = 0.821) for the measurement of smoking stages. Examination of the smoking cessation stages in a sample of 218 students in the cessation stage demonstrated that the results for five classes could be interpreted (G 2 = 0.001, df = 1, P = 0.975). Conclusions: The results suggested that this algorithm is clear, valid, and reliable.
Published: 2013

44. Position Reconstruction in LUX

Author: Collaboration, LUX, Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, Zhang, C, Collaboration, LUX, Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Boulton, EM, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Currie, A, Cutter, JE, Davison, TJR, Dobi, A, Druszkiewicz, E, Edwards, BN, Fallon, SR, Fan, A, Fiorucci, S, Gaitskell, RJ, Genovesi, J, Ghag, C, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pease, EK, Rhyne, C, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Velan, V, Verbus, JR, Webb, RC, White, JT, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, and Zhang, C
Abstract: The $(x, y)$ position reconstruction method used in the analysis of the complete exposure of the Large Underground Xenon (LUX) experiment is presented. The algorithm is based on a statistical test that makes use of an iterative method to recover the photomultiplier tube (PMT) light response directly from the calibration data. The light response functions make use of a two dimensional functional form to account for the photons reflected on the inner walls of the detector. To increase the resolution for small pulses, a photon counting technique was employed to describe the response of the PMTs. The reconstruction was assessed with calibration data including ${}^{\mathrm{83m}}$Kr (releasing a total energy of 41.5 keV) and ${}^{3}$H ($\beta^-$ with Q = 18.6 keV) decays, and a deuterium-deuterium (D-D) neutron beam (2.45 MeV). In the horizontal plane, the reconstruction has achieved an $(x, y)$ position uncertainty of $\sigma$= 0.82 cm for events of only 200 electroluminescence photons and $\sigma$ = 0.17 cm for 4,000 electroluminescence photons. Such signals are associated with electron recoils of energies $\sim$0.25 keV and $\sim$10 keV, respectively. The reconstructed position of the smallest events with a single electron emitted from the liquid surface has a horizontal $(x, y)$ uncertainty of 2.13 cm.
Published: 2017

45. Low-energy (0.7-74 keV) nuclear recoil calibration of the LUX dark matter experiment using D-D neutron scattering kinematics

Author: Collaboration, LUX, Akerib, DS, Alsum, S, Araújo, HM, Bai, X, Bailey, AJ, Balajthy, J, Beltrame, P, Bernard, EP, Bernstein, A, Biesiadzinski, TP, Whitis, TJ, Witherell, MS, Wolfs, FLH, Xu, J, Yazdani, K, Young, SK, Zhang, C, Boulton, EM, Bradley, A, Bramante, R, Brás, P, Byram, D, Cahn, SB, Carmona-Benitez, MC, Chan, C, Chapman, JJ, Chiller, AA, Chiller, C, Currie, A, Cutter, JE, Davison, TJR, Viveiros, LD, Dobi, A, Dobson, JEY, Druszkiewicz, E, Edwards, BN, Faham, CH, Fiorucci, S, Gaitskell, RJ, Gehman, VM, Ghag, C, Gibson, KR, Gilchriese, MGD, Hall, CR, Hanhardt, M, Haselschwardt, SJ, Hertel, SA, Hogan, DP, Horn, M, Huang, DQ, Ignarra, CM, Ihm, M, Jacobsen, RG, Ji, W, Kamdin, K, Kazkaz, K, Khaitan, D, Knoche, R, Larsen, NA, Lee, C, Lenardo, BG, Lesko, KT, Lindote, A, Lopes, MI, Malling, DC, Manalaysay, A, Mannino, RL, Marzioni, MF, McKinsey, DN, Mei, DM, Mock, J, Moongweluwan, M, Morad, JA, Murphy, ASJ, Nehrkorn, C, Nelson, HN, Neves, F, O'Sullivan, K, Oliver-Mallory, KC, Palladino, KJ, Pangilinan, M, Pease, EK, Phelps, P, Reichhart, L, Rhyne, CA, Shaw, S, Shutt, TA, Silva, C, Solmaz, M, Solovov, VN, Sorensen, P, Stephenson, S, Sumner, TJ, Szydagis, M, Taylor, DJ, Taylor, WC, Tennyson, BP, Terman, PA, Tiedt, DR, To, WH, Tripathi, M, Tvrznikova, L, Uvarov, S, Verbus, JR, Webb, RC, and White, JT
Subjects: Physics::Instrumentation and Detectors, hep-ex, Astrophysics::Instrumentation and Methods for Astrophysics, Nuclear Experiment, physics.ins-det, astro-ph.IM
Abstract: The Large Underground Xenon (LUX) experiment is a dual-phase liquid xenon time projection chamber (TPC) operating at the Sanford Underground Research Facility in Lead, South Dakota. A calibration of nuclear recoils in liquid xenon was performed $\textit{in situ}$ in the LUX detector using a collimated beam of mono-energetic 2.45 MeV neutrons produced by a deuterium-deuterium (D-D) fusion source. The nuclear recoil energy from the first neutron scatter in the TPC was reconstructed using the measured scattering angle defined by double-scatter neutron events within the active xenon volume. We measured the absolute charge ($Q_{y}$) and light ($L_{y}$) yields at an average electric field of 180 V/cm for nuclear recoil energies spanning 0.7 to 74 keV and 1.1 to 74 keV, respectively. This calibration of the nuclear recoil signal yields will permit the further refinement of liquid xenon nuclear recoil signal models and, importantly for dark matter searches, clearly demonstrates measured ionization and scintillation signals in this medium at recoil energies down to $\mathcal{O}$(1 keV).
Published: 2016

46. Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment

Author: Collaboration, LUX, Akerib, D. S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., Bernard, E. P., Bernstein, A., Biesiadzinski, T. P., Boulton, E. M., Bradley, A., Bramante, R., Cahn, S. B., Carmona-Benitez, M. C., Chan, C., Chapman, J. J., Chiller, A. A., Chiller, C., Currie, A., Cutter, J. E., Davison, T. J. R., Viveiros, L. de, Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Edwards, B. N., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Gehman, V. M., Ghag, C., Gibson, K. R., Gilchriese, M. G. D., Hall, C. R., Hanhardt, M., Haselschwardt, S. J., Hertel, S. A., Hogan, D. P., Horn, M., Huang, D. Q., Ignarra, C. M., Ihm, M., Jacobsen, R. G., Ji, W., Kazkaz, K., Khaitan, D., Knoche, R., Larsen, N. A., Lee, C., Lenardo, B. G., Lesko, K. T., Lindote, A., Lopes, M. I., Malling, D. C., Manalaysay, A., Mannino, R. L., Marzioni, M. F., McKinsey, D. N., Mei, D. M., Mock, J., Moongweluwan, M., Morad, J. A., Murphy, Alex, Nehrkorn, C., Nelson, H. N., Neves, F., O'Sullivan, K., Oliver-Mallory, K. C., Ott, R. A., Palladino, K. J., Pangilinan, M., Pease, E. K., Phelps, P., Reichhart, L., Rhyne, C., Shaw, S., Shutt, T. A., Silva, C., Solovov, V. N., Sorensen, P., Stephenson, S., Sumner, T. J., Szydagis, M., Taylor, D. J., Taylor, W., Tennyson, B. P., Terman, P. A., Tiedt, D. R., To, W. H., Tripathi, M., Tvrznikova, L., Uvarov, S., Verbus, J. R., Webb, R. C., White, J. T., Whitis, T. J., Witherell, M. S., Wolfs, F. L. H., Yazdani, K., Young, S. K., Zhang, C., Science and Technology Facilities Council (STFC), and The Royal Society
Subjects: General Physics, Physics::Instrumentation and Detectors, Physics, Multidisciplinary, Dark matter, Massive particle, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 09 Engineering, High Energy Physics - Experiment, LUX Collaboration, Nuclear physics, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Xenon, Recoil, 0103 physical sciences, DARK-MATTER, Nuclear Experiment, 010306 general physics, 01 Mathematical Sciences, Physics, Science & Technology, 02 Physical Sciences, Time projection chamber, 010308 nuclear & particles physics, Scattering, hep-ex, Astrophysics::Instrumentation and Methods for Astrophysics, hep-ph, 3. Good health, High Energy Physics - Phenomenology, chemistry, Weakly interacting massive particles, Physical Sciences, High Energy Physics::Experiment, Nucleon
Abstract: We present the first experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of $1.4~\times~10^{4}~\text{kg}\cdot~\text{days}$ of fiducial exposure allows 90% CL upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of $\sigma_n~=~9.4~\times~10^{-41}~\text{cm}^2$ ($\sigma_p~=~2.9~\times~10^{-39}~\text{cm}^2$) at 33 GeV/c$^2$. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date., Comment: 6 pages, 2 figures
Published: 2016

47. Establishment of New Evaluation and Accreditation system for Graduate Medical Education in Iran

Author: Mirzazadeh A, Hashemi H, Naseripour H, Fotouhi A, Yazdani K, Tavakoli S, Raisi B, and Taj M
Subjects: lcsh:R5-920, PROGRAM EVALUATION, education, IRAN, ACCREDITATION, lcsh:L7-991, lcsh:Medicine (General), geographic locations, GRADUATEMEDICAL EDUCATION, lcsh:Education (General)
Abstract: Graduate Medical Education is one of the stage of the continuum of medical education in Iran. At present, near 5500 residents are being trained in 24 specialties and 21 subspecialties in 26 Universities of Medical Sciences. Based on a special Act of National Parliament in 1973, the Iranian Council for Graduate Medical Education is responsible for supervision on the quality of Graduate Medical Education. Despite significant activities in this field during last three decades, there has been no integrated effort for evaluation and accreditation of specialty education units, yet. In this regard, the Secretary of the Council appointed a committee for preliminary studies and presentation of new approaches. In this article, the authors first describe the details of the activities of this committee. Thereafter, challenges of Graduate Medical Education and relevant supervisory bodies have been discussed. In the end, activities for the establishment of new accreditation system of Graduate Medical Education in Iran have been described. Key words: GRADUATEMEDICAL EDUCATION, ACCREDITATION, IRAN, PROGRAM EVALUATION
Published: 2004

48. Functional and technological evolution of enterprise systems: An overview

Author: Yazdani Rashvanlouei, K., primary, Thome, R., additional, and Yazdani, K., additional
Published: 2015
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49. Substance abuse in high school students in association with socio-demographic variables in northwest of iran

Author: Mohammadpoorasl, A., Nedjat, S., Ali Fakhari, Yazdani, K., Rahimi Foroushani, A., and Fotouhi, A.
Subjects: Substance abuse, lcsh:Public aspects of medicine, Smoking, Original Article, lcsh:RA1-1270, Risk taking behavior, Iran, Adolescents
Abstract: Background: Substance abuse in adolescents and its often tragic consequences, including addiction, is one of the preventable major public health problems. The aims of this paper were to estimate the prevalence of substance abuse and to evaluate its some associated factors in adolescents of Tabriz City (northwest of Iran). Methods: A self-administered questionnaire was completed in 4903 randomly selected students with mean age of 15.7 years old. The aim of the questionnaire was obtaining information on substance abuse, socio-economical information, cigarette smoking behavior, general risk taking behavior, self-esteem, attitude towards smoking and self-injury as well as demographical characteristics. Results: Prevalence of substance abuse was 1.4% (95% CI: 1.1–1.7) which was different statistically significant between boys (2.4%) and girls (0.6%) (P
Published: 2012

50. 3D Analysis of Magnetohydrodynamic (MHD) Micropump Performance Using Numerical Method

Author: Derakhshan, S., primary and Yazdani, K., additional
Published: 2015
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