367 research outputs found
Constraints on dark matter protohalos in effective theories and neutrinophilic dark matter
No full textAbstractThe mass of primordial dark matter (DM) protohalos remains unknown. However, the missing satellites problem may be an indication that they are quite large. In this paper, we use effective field theory to map constraints on dark matter-SM interactions into limits on the mass of DM protohalos. Given that leptons remain in the thermal bath until late times, we focus on their interactions with DM. To illustrate the method, we use the null results of LEP missing energy searches along with Fermi-LAT searches for DM annihilation in nearby dwarf galaxies, to derive limits on the protohalo mass, ≲ (10−6 to 10−1) M⊙, with the range depending on the DM mass and the operator. Thus, if DM is to remain thermally coupled until late times and account for the missing satellites, charged lepton interactions are insufficient. This motivates neutrinophilic DM, which can have protohalo masses orders of magnitude larger, with constraints arising from Planck, IceCube and unpublished Super-K data. We show that effective neutrinophilic models offer a viable solution to the missing satellites problem for sub-GeV DM masses with larger than WIMP-sized annihilation cross sections
Solar neutrinos as a probe of dark matter-neutrino interactions
No full textSterile neutrinos at the eV scale have long been studied in the context of anomalies in short baseline neutrino experiments. Their cosmology can be made compatible with our understanding of the early Universe provided the sterile neutrino sector enjoys a nontrivial dynamics with exotic interactions, possibly providing a link to the Dark Matter (DM) puzzle. Interactions between DM and neutrinos have also been proposed to address the long-standing "missing satellites" problem in the field of large scale structure formation. Motivated by these considerations, in this paper we discuss realistic scenarios with light steriles coupled to DM . We point out that within this framework active neutrinos acquire an effective coupling to DM that manifests itself as a new matter potential in the propagation within a medium of asymmetric DM . Assuming that at least a small fraction of asymmetric DM has been captured by the Sun, we show that a sizable region of the parameter space of these scenarios can be probed by solar neutrino experiments, especially in the regime of small couplings and light mediators where all other probes become inefficient. In the latter regime these scenarios behave as familiar 3+1 models in all channels except for solar data, where a Solar Dark MSW effect takes place. Solar Dark MSW is characterized by modifications of the most energetic 8B and CNO neutrinos, whereas the other fluxes remain largely unaffected
Enhancing the sensitivity to seesaw mechanism predictions in gauged <math display="inline"><mi>B</mi><mo>-</mo><mi>L</mi></math> scenarios
No full textNew gauge bosons coupled to heavy neutral leptons (HNLs) are simple and well-motivated extensions of the Standard Model. In searches for HNLs in proton fixed-target experiments, we find that a large population of gauge bosons (Z′) produced by proton bremsstrahlung may decay to HNLs, leading to a significant improvement in existing bounds on the (mHNL,Uα), where Uα represent the mixing between HNL and the active neutrinos with flavor α. We study this possibility in fixed target experiments with the 8 GeV proton beams, including SBND, MicroBooNE, and ICARUS, as well as DUNE and DarkQuest at 120 GeV. We find the projected sensitivities to additional Z′-mediated HNL production can bring the seesaw mechanism of the neutrino masses within a broadened experimental reach.New gauge bosons coupled to heavy neutral leptons (HNLs) are simple and well-motivated extensions of the Standard Model. In searches for HNLs in proton fixed-target experiments, we find that a large population of gauge bosons () produced by proton bremsstrahlung may decay to HNLs, leading to a significant improvement in existing bounds on the (), where represent the mixing between HNL and the active neutrinos with flavor . We study this possibility in fixed target experiments with the 8 GeV proton beams, including SBND, MicroBooNE, and ICARUS, as well as DUNE and DarkQuest at 120 GeV. We find the projected sensitivities to additional -mediated HNL production can bring the seesaw mechanism of the neutrino masses within a broadened experimental reach
Enhancing the Sensitivity to Seesaw Predictions in Gauged B-L Scenarios
No full textNew gauge bosons coupled to heavy neutral leptons (HNLs) are simple and well-motivated extensions of the Standard Model. In searches for HNLs in proton fixed-target experiments, we find that a large population of gauge bosons () produced by proton bremsstrahlung may decay to HNLs, leading to a significant improvement in existing bounds on the (), where represent the mixing between HNL and the active neutrinos with flavor . We study this possibility in fixed target experiments with the 8 GeV proton beams, including SBND, MicroBooNE, and ICARUS, as well as DUNE and DarkQuest at 120 GeV. We find the projected sensitivities to additional
-mediated HNL production can bring the seesaw mechanism of the neutrino masses within a broadened experimental reach
Physical Review D
No full textNew gauge bosons coupling to leptons are simple and well-motivated extensions of the Standard Model. We study the sensitivity to gauged L-mu- L-e, L-e - L-tau and L-mu- L-tau both with the existing beam dump mode data of MiniBooNE and with the DUNE near detector. We find that including bremsstrahlung and resonant production of Z' which decays to e(+/-) and mu(+/-) final states leads to a significant improvement in existing bounds, especially for L-mu- L-e and L-e - L-tau for DUNE while competitive constraints can be achieved with the existing data from the MiniBooNE's beam dump run.U.S. Department of Energy [DE-SC0011686]Published versionWe are very grateful to Andrea Celentano and Luc Darme for helpful conversations. The work of F. C. and I. M. S. is supported by the U.S. Department of Energy under the Award No. DE-SC0020250. The work of B. D. and A. T. is supported in part by the U.S. Department of Energy under the Award No. DE-SC0010813. The work of G. G., W. J., and J. Y. are supported by the U.S. Department of Energy under the Award No. DE-SC0011686
Sterile Neutrino Searches
No full textIn the first part of the thesis we explore the sensitivity to sterile neutrinos by using a novel kaon tagging technology: ENUBET, the proposed experiment could decisively test indications from the experiments Neutrino-4 and IceCube. In the second part of the thesis we discuss the current status of sterile neutrino searches at nuclear reactors, we present a study with the optimization of a green field, two baseline reactor experiment with respect to the sensitivity for electron anti-neutrino disappearance in search of a light sterile neutrino at both research and commercial reactors. We find that a total of 5 tons of detectors deployed at a commercial reactor with a closest approach of 25 m can probe the mixing angle sin²2θ down to ∼ 5 × 10⁻³ around ∆m² ∼ 1 eV² . The same detector mass deployed at a research reactor can be sensitive up to ∆m² ∼ 20 − 30 eV² assuming a closest approach of 3 m and excellent energy resolution, such as that projected for TAO. We also find that lithium doping of the reactor could be effective in increasing the sensitivity for higher ∆m² values.Master of ScienceA sterile neutrino is a particle that is not included in the actual content of matter at the fundamental level. Our goal in this thesis was to search for an imprint of this particle at neutrino experiments. We performed numerical simulations using the experimental specification given in the literature to predict what this signal should look like. The importance of searching for this particle arises from indications at neutrino nuclear experiments, if this particle exists, that would imply new physics beyond our actual understanding of the matter content in the universe. The first search was performed at an experimental facility called ENUBET and the second search was performed at nuclear reactors. Testing this elusive particle means we need to determine two parameters from a model. The results of the aforementioned parameter space searches are presented in this thesis. The statistical significance in our findings is not entirely conclusive to either confirm or refute the sterile neutrino. The benefits of studying neutrinos at nuclear reactors is that they are produced in generating electrical power as well as monitoring nuclear weapons
Physical Review Letters
No full textProton and neutron decays into light new particles X can drastically change the experimental signatures and benefit from the complementarity of large water-Cherenkov neutrino detectors such as Super- and Hyper-Kamiokande and tracking detectors such as JUNO and DUNE. The proton decays p → ⁺X and p → π⁺X with mX near phase-space closure lead to charged particles below the Cherenkov threshold, rendering them practically invisible in Super- and Hyper-Kamiokande but not in JUNO and DUNE, which are therefore uniquely positioned for these baryon-number-violating signatures despite their smaller size. As an additional signature, such nucleon decays in the Earth can produce a sizable flux of X particles in underground detectors.We present a simple model in which nucleons decay into sub-GeV sterile neutrinos that subsequently decay through active-sterile neutrino mixing, with a promisingly large number of events in Super-Kamiokande even in the seesaw-motivated parameter space.This work was supported by a 4-VA at UVA Collaborative Research Grant and by the U.S. Department of Energy under Grants No. DE-SC0007974 (J. H.) and No. DE-SC0020262 (I. M. S.).Published versio
Mapping the Neutrino Floor for Direct Detection Experiments Based on Dark Matter-Electron Scattering
No full textWe study the discovery reach of future Dark Matter (DM) Direct Detection experiments using DM-electron scattering in the presence of the solar neutrino background. At these low energies traditional methods for nuclear and electronic recoil discrimination fail, implying that the neutrino- nucleusscattering background can be sizable. We calculate discovery limits based on ionization values of signal and background, and quantify the dependence on the ionization model. Moreover, we explore how the dependence of the DM cross section discovery limits varies with exposure, electronic/nuclear recoil discrimination, DM form factors, and DM astrophysical uncertainties
Indigenous Nations Journal, Volume 4, Number 1 (Spring, 2003): Book Review
No full text"Dine: A History of the Navajo" by Peter Iverson (Nathan Wilson); "Many Faces of Gender: Roles and Relationships Through Time in Indigenous Norther Communities" by lisa Frink, Rita S. Shepard, and Gregory A. Reinhardt (Christie Firtha); "Chief Daniel Bread" by Laurence M. Hauptman and L. Gordon McLester III (Daniel M. Cobb); "Women and Power in Native North America" edited by Laura F. Klein and Lillian Ackerman (Ian Chambers); "Navajo Saddle Blankets" edited by Lane Coulter (John Pinson); "Trying to Get It Back: Indigenous Women, Education and Culture" by Gillian Weiss (Patricia Ploesch); "Viola Martinez, California Paiute: Living in Two Worlds" by Diana Meyers Bahr (Cassandra Sandrane); "Yuchi Ceremonial Life: Performance, Meaning, and Tradition in a Contemporary American Indian Community" by Jason Baird Jackson (Andrew K. Frank); "Clearing a Path: Theoretical Approaches to the Past in Native American Studies" edited by Nancy Shoemaker (Sterling Fluharty); "Defending the Land: Sovereignity and Forest Life in James Bay Cree Society" by Ronald Niezen (Yale Belanger
- …
