The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Malcolm Fairbairn - One of the best experts on this subject based on the ideXlab platform.
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spin independent elastic wimp scattering and the Dama annual modulation signal
Journal of Cosmology and Astroparticle Physics, 2009Co-Authors: Malcolm Fairbairn, Thomas SchwetzAbstract:We discuss the interpretation of the annual modulation signal seen in the Dama experiment in terms of spin-independent elastic WIMP scattering. Taking into account channeling in the crystal as well as the spectral signature of the modulation signal we find that the low-mass WIMP region consistent with Dama data is confined to WIMP masses close to m� ≃ 12GeV, in disagreement with the constraints from CDMS and XENON. We conclude that even if channeling is taken into account this interpretation of the Dama modulation signal is disfavoured. There are no overlap regions in the parameter space at 90% CL and a consistency test gives the probability of 1.2 ×10 −5 . We study the robustness of this result with respect to variations of the WIMP velocity distribution in our galaxy, by changing various parameters of the distribution function, and by using the results of a realistic N-body dark matter simulation. We find that only by making rather extreme assumptions regarding halo properties can we obtain agreement between Dama and CDMS/XENON.
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spin independent elastic wimp scattering and the Dama annual modulation signal
arXiv: High Energy Physics - Phenomenology, 2008Co-Authors: Malcolm Fairbairn, Thomas SchwetzAbstract:We discuss the interpretation of the annual modulation signal seen in the Dama experiment in terms of spin-independent elastic WIMP scattering. Taking into account channeling in the crystal as well as the spectral signature of the modulation signal we find that the low-mass WIMP region consistent with Dama data is confined to WIMP masses close to $m_\chi \simeq 12$ GeV, in disagreement with the constraints from CDMS and XENON. We conclude that even if channeling is taken into account this interpretation of the Dama modulation signal is disfavoured. There are no overlap regions in the parameter space at 90% CL and a consistency test gives the probability of $1.2\times 10^{-5}$. We study the robustness of this result with respect to variations of the WIMP velocity distribution in our galaxy, by changing various parameters of the distribution function, and by using the results of a realistic N-body dark matter simulation. We find that only by making rather extreme assumptions regarding halo properties can we obtain agreement between Dama and CDMS/XENON.
Kathryn M Zurek - One of the best experts on this subject based on the ideXlab platform.
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new Dama dark matter window and energetic neutrino searches
Physical Review D, 2009Co-Authors: Dan Hooper, Frank Petriello, Kathryn M Zurek, Marc KamionkowskiAbstract:Recently, the Dama/LIBRA Collaboration has repeated and reinforced their claim to have detected an annual modulation in their signal rate, and have interpreted this observation as evidence for dark-matter particles at the 8.2σ confidence level. Furthermore, it has also been noted that the effects of channeling may enable a weakly interacting massive particle (WIMP) that scatters elastically via spin-independent interactions from nuclei to produce the signal observed by Dama/LIBRA without exceeding the limits placed by CDMS, XENON, CRESST, CoGeNT, and other direct-detection experiments. To accommodate this elastic-scattering explanation, however, the mass of the responsible dark-matter particle must be relatively light, mDM ≾ 10 GeV. Such dark-matter particles will become captured by and annihilate in the Sun at very high rates, leading to a potentially large flux of GeV-scale neutrinos. We calculate the neutrino spectrum resulting from WIMP annihilations in the Sun and show that existing limits from Super-Kamiokande can be used to close a significant portion of the Dama region, especially if the dark-matter particles produce tau leptons or neutrinos in a sizable fraction of their annihilations. We also determine the spin-dependent WIMP-nuclei elastic-scattering parameter space consistent with Dama. The constraints from Super-Kamiokande on the spin-dependent scenario are even more severe—they exclude any self-annihilating WIMP in the Dama region that annihilates 1% of the time or more to any combination of neutrinos, tau leptons, or charm or bottom quarks.
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Dama and wimp dark matter
Journal of High Energy Physics, 2008Co-Authors: Frank Petriello, Kathryn M ZurekAbstract:We study whether spin-independent scattering of weakly-interacting massive particles (WIMPs) with nuclei can account for the annual modulation signal reported by Dama. We consider both elastic and inelastic scattering processes. We find that there is a region of WIMP parameter space which can simultaneously accommodate Dama and the null results of CDMS, CRESST, and XENON. This region corresponds to an ordinary, elastically-scattering WIMP with a standard Maxwell-Boltzmann distribution, a mass 3mDM8, and a spin-independent cross section with nucleons 3 × 10−412σpSI5 × 10−392. This new region of parameter space depends crucially on the effect of channeling on the energy threshold for WIMP detection in the Dama experiment; without the inclusion of this effect, the Dama allowed region is essentially closed by null experiments. Such low-mass WIMPs arise in many theories of Beyond the Standard Model physics, from minimal extensions of the MSSM to solutions of the baryon-dark matter coincidence problem. We find that inelastic scattering channels do not open up a significant parameter region consistent with all experimental results. Future experiments with low energy thresholds for detecting nuclear recoils, such as CDMSII-Si and those utilizing ultra-low energy germanium detectors, will be able to probe the Dama region of parameter space.
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Dama and wimp dark matter
arXiv: High Energy Physics - Phenomenology, 2008Co-Authors: Frank Petriello, Kathryn M ZurekAbstract:We study whether spin-independent scattering of weakly-interacting massive particles (WIMPs) with nuclei can account for the annual modulation signal reported by Dama. We consider both elastic and inelastic scattering processes. We find that there is a region of WIMP parameter space which can simultaneously accommodate Dama and the null results of CDMS, CRESST, and XENON. This region corresponds to an ordinary, elastically-scattering WIMP with a standard Maxwell-Boltzmann distribution, a mass 3 GeV < m_{DM} <8 GeV, and a spin-independent cross section with nucleons 3 \times 10^{-41} cm^2 < \sigma_p^{SI} < 5 \times 10^{-39} cm^2. This new region of parameter space depends crucially on the recently discovered effect of channeling on the energy threshold for WIMP detection in the Dama experiment; without the inclusion of this effect, the Dama allowed region is essentially closed by null experiments. Such low-mass WIMPs arise in many theories of Beyond the Standard Model physics, from minimal extensions of the MSSM to solutions of the baryon-dark matter coincidence problem. We find that inelastic scattering channels do not open up a significant parameter region consistent with all experimental results. Future experiments with low energy thresholds for detecting nuclear recoils, such as CDMSII-Si and those utilizing ultra-low energy germanium detectors, will be able to probe the Dama region of parameter space.
Thomas Schwetz - One of the best experts on this subject based on the ideXlab platform.
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spin independent elastic wimp scattering and the Dama annual modulation signal
Journal of Cosmology and Astroparticle Physics, 2009Co-Authors: Malcolm Fairbairn, Thomas SchwetzAbstract:We discuss the interpretation of the annual modulation signal seen in the Dama experiment in terms of spin-independent elastic WIMP scattering. Taking into account channeling in the crystal as well as the spectral signature of the modulation signal we find that the low-mass WIMP region consistent with Dama data is confined to WIMP masses close to m� ≃ 12GeV, in disagreement with the constraints from CDMS and XENON. We conclude that even if channeling is taken into account this interpretation of the Dama modulation signal is disfavoured. There are no overlap regions in the parameter space at 90% CL and a consistency test gives the probability of 1.2 ×10 −5 . We study the robustness of this result with respect to variations of the WIMP velocity distribution in our galaxy, by changing various parameters of the distribution function, and by using the results of a realistic N-body dark matter simulation. We find that only by making rather extreme assumptions regarding halo properties can we obtain agreement between Dama and CDMS/XENON.
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spin independent elastic wimp scattering and the Dama annual modulation signal
arXiv: High Energy Physics - Phenomenology, 2008Co-Authors: Malcolm Fairbairn, Thomas SchwetzAbstract:We discuss the interpretation of the annual modulation signal seen in the Dama experiment in terms of spin-independent elastic WIMP scattering. Taking into account channeling in the crystal as well as the spectral signature of the modulation signal we find that the low-mass WIMP region consistent with Dama data is confined to WIMP masses close to $m_\chi \simeq 12$ GeV, in disagreement with the constraints from CDMS and XENON. We conclude that even if channeling is taken into account this interpretation of the Dama modulation signal is disfavoured. There are no overlap regions in the parameter space at 90% CL and a consistency test gives the probability of $1.2\times 10^{-5}$. We study the robustness of this result with respect to variations of the WIMP velocity distribution in our galaxy, by changing various parameters of the distribution function, and by using the results of a realistic N-body dark matter simulation. We find that only by making rather extreme assumptions regarding halo properties can we obtain agreement between Dama and CDMS/XENON.
Frank Petriello - One of the best experts on this subject based on the ideXlab platform.
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new Dama dark matter window and energetic neutrino searches
Physical Review D, 2009Co-Authors: Dan Hooper, Frank Petriello, Kathryn M Zurek, Marc KamionkowskiAbstract:Recently, the Dama/LIBRA Collaboration has repeated and reinforced their claim to have detected an annual modulation in their signal rate, and have interpreted this observation as evidence for dark-matter particles at the 8.2σ confidence level. Furthermore, it has also been noted that the effects of channeling may enable a weakly interacting massive particle (WIMP) that scatters elastically via spin-independent interactions from nuclei to produce the signal observed by Dama/LIBRA without exceeding the limits placed by CDMS, XENON, CRESST, CoGeNT, and other direct-detection experiments. To accommodate this elastic-scattering explanation, however, the mass of the responsible dark-matter particle must be relatively light, mDM ≾ 10 GeV. Such dark-matter particles will become captured by and annihilate in the Sun at very high rates, leading to a potentially large flux of GeV-scale neutrinos. We calculate the neutrino spectrum resulting from WIMP annihilations in the Sun and show that existing limits from Super-Kamiokande can be used to close a significant portion of the Dama region, especially if the dark-matter particles produce tau leptons or neutrinos in a sizable fraction of their annihilations. We also determine the spin-dependent WIMP-nuclei elastic-scattering parameter space consistent with Dama. The constraints from Super-Kamiokande on the spin-dependent scenario are even more severe—they exclude any self-annihilating WIMP in the Dama region that annihilates 1% of the time or more to any combination of neutrinos, tau leptons, or charm or bottom quarks.
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Dama and wimp dark matter
Journal of High Energy Physics, 2008Co-Authors: Frank Petriello, Kathryn M ZurekAbstract:We study whether spin-independent scattering of weakly-interacting massive particles (WIMPs) with nuclei can account for the annual modulation signal reported by Dama. We consider both elastic and inelastic scattering processes. We find that there is a region of WIMP parameter space which can simultaneously accommodate Dama and the null results of CDMS, CRESST, and XENON. This region corresponds to an ordinary, elastically-scattering WIMP with a standard Maxwell-Boltzmann distribution, a mass 3mDM8, and a spin-independent cross section with nucleons 3 × 10−412σpSI5 × 10−392. This new region of parameter space depends crucially on the effect of channeling on the energy threshold for WIMP detection in the Dama experiment; without the inclusion of this effect, the Dama allowed region is essentially closed by null experiments. Such low-mass WIMPs arise in many theories of Beyond the Standard Model physics, from minimal extensions of the MSSM to solutions of the baryon-dark matter coincidence problem. We find that inelastic scattering channels do not open up a significant parameter region consistent with all experimental results. Future experiments with low energy thresholds for detecting nuclear recoils, such as CDMSII-Si and those utilizing ultra-low energy germanium detectors, will be able to probe the Dama region of parameter space.
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Dama and wimp dark matter
arXiv: High Energy Physics - Phenomenology, 2008Co-Authors: Frank Petriello, Kathryn M ZurekAbstract:We study whether spin-independent scattering of weakly-interacting massive particles (WIMPs) with nuclei can account for the annual modulation signal reported by Dama. We consider both elastic and inelastic scattering processes. We find that there is a region of WIMP parameter space which can simultaneously accommodate Dama and the null results of CDMS, CRESST, and XENON. This region corresponds to an ordinary, elastically-scattering WIMP with a standard Maxwell-Boltzmann distribution, a mass 3 GeV < m_{DM} <8 GeV, and a spin-independent cross section with nucleons 3 \times 10^{-41} cm^2 < \sigma_p^{SI} < 5 \times 10^{-39} cm^2. This new region of parameter space depends crucially on the recently discovered effect of channeling on the energy threshold for WIMP detection in the Dama experiment; without the inclusion of this effect, the Dama allowed region is essentially closed by null experiments. Such low-mass WIMPs arise in many theories of Beyond the Standard Model physics, from minimal extensions of the MSSM to solutions of the baryon-dark matter coincidence problem. We find that inelastic scattering channels do not open up a significant parameter region consistent with all experimental results. Future experiments with low energy thresholds for detecting nuclear recoils, such as CDMSII-Si and those utilizing ultra-low energy germanium detectors, will be able to probe the Dama region of parameter space.
R Bernabei - One of the best experts on this subject based on the ideXlab platform.
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the Dama project achievements implications and perspectives
Progress in Particle and Nuclear Physics, 2020Co-Authors: R Bernabei, P Belli, Andrea Bussolotti, F Cappella, V Caracciolo, R Cerulli, C J Dai, A Dangelo, Alessandro Di MarcoAbstract:Abstract Experimental observations and theoretical arguments at galactic and larger scales pointed out that a large fraction of the Universe is composed of Dark Matter (DM) particles. This has motivated the pioneer Dama experimental efforts to investigate the presence of such particles in the galactic halo, by exploiting a model independent signature and very highly radio-pure apparatus in deep underground. In this paper, after a short introductory part, the long-standing model-independent annual modulation effect measured by Dama Collaboration, with various experimental configurations, is examined. In the energy region between 2 and 6 keV, the data from Dama/NaI, Dama/LIBRA-phase1 and Dama/LIBRA-phase2 (full exposure: 2.46 ton × yr) confirm the evidence of a signal that meets all the several specific requirements of the exploited model independent DM annual modulation signature, at 12.9 σ C.L. The Dama/LIBRA-phase2 configuration, profiting from new high quantum efficiency photomultipliers, new electronics and other improvements with respect to Dama/LIBRA-phase1, has also allowed the confirmation of such an evidence down to a software energy threshold of 1 keV. The complexity and the uncertainties of corollary model dependent quests for the DM candidate particle(s) and related scenarios are also addressed at some extent and several of the many possibilities are examined. The efforts towards the new phase3 of the experiment are summarized, showing the strategies and the results obtained with the present developments.
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first results from Dama libra phase2
Nuclear and Particle Physics Proceedings, 2018Co-Authors: R Bernabei, P Belli, Andrea Bussolotti, F Cappella, V Caracciolo, R Cerulli, C J Dai, A Dangelo, Alessandro Di Marco, A IncicchittiAbstract:Abstract The first results obtained by the Dama/LIBRA–phase2 experiment with the data collected deep underground at the Gran Sasso National Laboratory over 6 independent annual cycles (corresponding to a total exposure of 1.13 ton × yr) are presented. The Dama/LIBRA–phase2 apparatus, about 250 kg highly radio-pure NaI(Tl), profits of a second generation high quantum efficiency photomultipliers and of new electronics; in the new configuration the software energy threshold is at 1 keV. The Dama/LIBRA–phase2 data confirm the evidence of a signal that meets all the requirements of the model independent Dark Matter annual modulation signature, at 9.5 σ C.L. in the energy region (1-6) keV. In the energy region between 2 and 6 keV, where data are also available from Dama/NaI and Dama/LIBRA–phase1 the achieved C.L. for the full exposure (2.46 ton × yr) is 12.9 σ.
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first model independent results from Dama libra phase2
Universe, 2018Co-Authors: R Bernabei, P Belli, Andrea Bussolotti, F Cappella, V Caracciolo, R Cerulli, C J Dai, A Dangelo, Alessandro Di Marco, A IncicchittiAbstract:The first results obtained by the Dama/LIBRA–phase2 experiment are presented. The data have been collected over six independent annual cycles corresponding to a total exposure of 1.13 ton × year, deep underground at the Gran Sasso National Laboratory. The Dama/LIBRA–phase2 apparatus, about 250 kg highly radio-pure NaI(Tl), profits from a second generation high quantum efficiency photomultipliers and of new electronics with respect to Dama/LIBRA–phase1. The improved experimental configuration has also allowed to lower the software energy threshold. The Dama/LIBRA–phase2 data confirm the evidence of a signal that meets all the requirements of the model independent Dark Matter annual modulation signature, at 9.5 σ C.L. in the energy region (1–6) keV. In the energy region between 2 and 6 keV, where data are also available from Dama/NaI and Dama/LIBRA–phase1, the achieved C.L. for the full exposure (2.46 ton × year) is 12.9 σ .
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first model independent results from Dama libra phase2
arXiv: High Energy Physics - Experiment, 2018Co-Authors: R Bernabei, P Belli, Andrea Bussolotti, F Cappella, V Caracciolo, R Cerulli, C J Dai, A Dangelo, Alessandro Di Marco, A IncicchittiAbstract:The first model independent results obtained by the Dama/LIBRA-phase2 experiment are presented. The data have been collected over 6 annual cycles corresponding to a total exposure of 1.13 ton $\times$ yr, deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. The Dama/LIBRA-phase2 apparatus, $\simeq$ 250 kg highly radio-pure NaI(Tl), profits from a second generation high quantum efficiency photomultipliers and of new electronics with respect to Dama/LIBRA-phase1. The improved experimental configuration has also allowed to lower the software energy threshold. New data analysis strategies are presented. The Dama/LIBRA-phase2 data confirm the evidence of a signal that meets all the requirements of the model independent Dark Matter (DM) annual modulation signature, at 9.5 $\sigma$ C.L. in the energy region (1-6) keV. In the energy region between 2 and 6 keV, where data are also available from Dama/NaI and Dama/LIBRA-phase1 (exposure $1.33$ ton $\times$ yr, collected over 14 annual cycles), the achieved C.L. for the full exposure (2.46 ton $\times$ yr) is 12.9 $\sigma$; the modulation amplitude of the single-hit scintillation events is: $(0.0103 \pm 0.0008)$ cpd/kg/keV, the measured phase is $(145 \pm 5)$ days and the measured period is $(0.999 \pm 0.001)$ yr, all these values are well in agreement with those expected for DM particles. No systematics or side reaction able to mimic the exploited DM signature (i.e. to account for the whole measured modulation amplitude and to simultaneously satisfy all the requirements of the signature), has been found or suggested by anyone throughout some decades thus far.
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final model independent results of Dama libra phase1 and perspectives of phase2
Physics of Particles and Nuclei, 2015Co-Authors: R Bernabei, P Belli, F Cappella, V Caracciolo, R Cerulli, C J Dai, A Dangelo, S Dangelo, S Castellano, Alessandro Di MarcoAbstract:This paper shortly summarizes the results obtained with the total exposure of 1.04 ton × yr collected by Dama/LIBRA-phase1 deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. during 7 annual cycles. The Dama/LIBRA-phase1 and the former Dama/NaI data (cumulative exposure 1.33 ton × yr, corresponding to 14 annual cycles) give evidence at 9.3 σ C.L. for the presence of Dark Matter (DM) particles in the galactic halo, on the basis of the exploited model independent DM annual modulation signature by using highly radio-pure NaI(Tl) target. The modulation amplitude of the single-hit events in the (2–6) keV energy interval is: (0.0112 ± 0.0012) cpd/kg/keV; the measured phase is (144 ± 7) days and the measured period is (0.998 ± 0.002) yr, values well in agreement with those expected for DM particles. No systematic or side reaction able to mimic the exploited DM signature has been found or suggested by anyone over more than a decade. Some of the perspectives of the presently running Dama/LIBRA-phase2 are outlined.
