Author
V M Datar
Bio: V M Datar is an academic researcher from Tata Institute of Fundamental Research. The author has contributed to research in topics: Dark matter & Light dark matter. The author has an hindex of 3, co-authored 3 publications receiving 30 citations.
Topics: Dark matter, Light dark matter, Pelletron
Papers
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TL;DR: In this article, the authors investigated the decay of a DMP into the channel of the channel δ − δ ≥ 1 to 50 GeV/c2, assuming that the channel saturates the decay width for the mass of the DMP.
Abstract: We report on the simulation studies addressing the possibility of dark matter particle (DMP) decaying into μ
+
μ
− channel. While not much is known about the properties of dark matter particles except through their gravitational effect, it has been recently conjectured that the so-called ‘anomalous Kolar events’ observed some decades ago may be due to the decay of unstable dark matter particles. The aim of this study is to see if this conjecture can be verified at the proposed iron calorimeter (ICAL) detector at INO. We study the possible decay to μ
± mode which may be seen in this detector with some modifications. For the purposes of simulation, we assume that the channel saturates the decay width for the mass ranging from 1 to 50 GeV/c2. The aim is not only to investigate the decay signatures, but also, more generally, to establish lower bounds on the lifetime of DMP even if no such decay takes place.
18 citations
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TL;DR: In this paper, the authors report on the simulation studies on the possibility of dark matter particle (DMP) decaying into leptonic modes, which may be seen in this detector with some modifications.
Abstract: We report on the simulation studies on the possibility of dark matter particle (DMP) decaying into leptonic modes. While not much is known about the properties of dark matter particles except through their gravitational effect, it has been recently conjectured that the so called "anomalous Kolar Events" observed some decades ago may be due to the decay of unstable dark matter particles (M.V.N. Murthy and G.Rajasekaran, Pramana, {\bf 82}, 609 (2014)). The aim of this study is to see if this conjecture can be verified at the proposed Iron Calorimeter (ICAL) detector at INO. We study the possible decay to leptonic modes which may be seen in this detector with some modifications. For the purposes of simulation we assume that each channel saturates the decay width for the mass ranging from $1-50 \rm{GeV/c^2}$. The aim is not only to investigate the decay signatures, but also, more generally, to establish lower bounds on the life time of DMP even if no such decay takes place.
8 citations
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TL;DR: An array of seven hexagonal NaI(Tl) detectors has been set up for measuringγ-ray spectra in the energy region 5 MeV ≤E ≥ 40 MeV with good accuracy as discussed by the authors.
Abstract: An array of seven hexagonal NaI(Tl) detectors has been set up for measuringγ-ray spectra in the energy region 5 MeV ≤E
γ ≤ 40 MeV with good accuracy. This is in contrast to earlier set ups which mostly used one large sized (about 10 inchesφ × 15 inches long)NaI(Tl) detector. This set up has been made for the study ofγ decay of GDR based on high spin states and ultra-dipole radiations. The array has been provided with the following features: a) TOF discrimination against neutrons, b) pile up detection and elimination, c) active and passive shielding to cut down background and d) an array of trigger counters for multiplicity dependence measurements. The well known program EGS4 has been used to determine the response of the array forγ-rays in the energy region 5–40 MeV and several test measurements have been carried out to confirm the validity of the calculated response functions. Some typicalγ-ray spectra fromα and16O induced reactions measured at VECC, Calcutta and Pelletron accelerator at TIFR are also shown.
5 citations
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TL;DR: Results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment revealed three WIMP-candidate events with a surface-event background estimate of 0.41, with a profile likelihood ratio test giving a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMp+background hypothesis.
Abstract: We report results of a search for Weakly Interacting Massive Particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg-days of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41^{+0.20}_{-0.08}(stat.)^{+0.28}_{-0.24}(syst.). Other known backgrounds from neutrons and 206Pb are limited to < 0.13 and <0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg-days for a recoil energy range of 7-100 keV for a WIMP of mass 10 GeV/c2. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6 GeV/c2 and WIMP-nucleon cross section of 1.9e-41 cm2.
428 citations
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TL;DR: The ordering of the neutrino masses is a crucial input for a deep understanding of flavor physics, and its determination may provide the key to establish the relationship among the lepton masses and mixings and their analogous properties in the quark sector as mentioned in this paper.
Abstract: The ordering of the neutrino masses is a crucial input for a deep understanding of flavor physics, and its determination may provide the key to establish the relationship among the lepton masses and mixings and their analogous properties in the quark sector The extraction of the neutrino mass ordering is a data-driven field expected to evolve very rapidly in the next decade In this review, we both analyze the present status and describe the physics of subsequent prospects Firstly, the different current available tools to measure the neutrino mass ordering are described Namely, reactor, long-baseline (accelerator and atmospheric) neutrino beams, laboratory searches for beta and neutrinoless double beta decays and observations of the cosmic background radiation and the large scale structure of the universe are carefully reviewed Secondly, the results from an up-to-date comprehensive global fit are reported: the Bayesian analysis to the 2018 publicly available oscillation and cosmological data sets provides strong evidence for the normal neutrino mass ordering versus the inverted scenario, with a significance of 35 standard deviations This preference for the normal neutrino mass ordering is mostly due to neutrino oscillation measurements Finally, we shall also emphasize the future perspectives for unveiling the neutrino mass ordering In this regard, apart from describing the expectations from the aforementioned probes, we also focus on those arising from alternative and novel methods, as 21 cm cosmology, core-collapse supernova neutrinos and the direct detection of relic neutrinos
206 citations
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TL;DR: In this paper, the authors presented the physics potential of the ICAL detector as obtained from realistic detector simulations and gave the expected physics reach of the detector with 10 years of runtime.
Abstract: The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies and path lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial to address some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations. We describe the simulation framework, the neutrino interactions in the detector, and the expected response of the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Its charge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles.
151 citations
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Panjab University, Chandigarh1, University of Calicut2, Saha Institute of Nuclear Physics3, Homi Bhabha National Institute4, Bhabha Atomic Research Centre5, Indian Institute of Technology Madras6, Indian Institute of Technology Bombay7, University of Calcutta8, Tata Institute of Fundamental Research9, Harish-Chandra Research Institute10, University of Delhi11, University of Mysore12, Physical Research Laboratory13, University of Lucknow14, Aligarh Muslim University15, University of Kashmir16, Jawaharlal Nehru University17, Variable Energy Cyclotron Centre18, American College, Madurai19, Utkal University20, Banaras Hindu University21
TL;DR: In this paper, the authors presented the physics potential of the ICAL detector as obtained from realistic detector simulations and gave the expected physics reach of the detector with 10 years of runtime.
Abstract: The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies and path lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial to address some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations. We describe the simulation framework, the neutrino interactions in the detector, and the expected response of the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Its charge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles.
116 citations
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TL;DR: In this article, the authors analyzed the current status of neutrino mass ordering and described the physics of subsequent prospects, as well as the different current available tools to measure the neutrinos mass ordering.
Abstract: The ordering of the neutrino masses is a crucial input for a deep understanding of flavor physics, and its determination may provide the key to establish the relationship among the lepton masses and mixings and their analogous properties in the quark sector. The extraction of the neutrino mass ordering is a data-driven field expected to evolve very rapidly in the next decade. In this review, we both analyze the present status and describe the physics of subsequent prospects. Firstly, the different current available tools to measure the neutrino mass ordering are described. Namely, reactor, long-baseline (accelerator and atmospheric) neutrino beams, laboratory searches for beta and neutrinoless double beta decays and observations of the cosmic background radiation and the large scale structure of the universe are carefully reviewed. Secondly, the results from an up-to-date comprehensive global fit are reported: the Bayesian analysis to the 2018 publicly available oscillation and cosmological data sets provides \emph{strong} evidence for the normal neutrino mass ordering versus the inverted scenario, with a significance of 3.5 standard deviations. This preference for the normal neutrino mass ordering is mostly due to neutrino oscillation measurements. Finally, we shall also emphasize the future perspectives for unveiling the neutrino mass ordering. In this regard, apart from describing the expectations from the aforementioned probes, we also focus on those arising from alternative and novel methods, as 21~cm cosmology, core-collapse supernova neutrinos and the direct detection of relic neutrinos.
111 citations