Search results for " neutrinos"
showing 10 items of 140 documents
Long-lived particles at the energy frontier: the MATHUSLA physics case
2019
We examine the theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of Standard Model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). In most cases the LLP lifetime can be treated as a free parameter from the $\mu$m scale up to the Big Bang Nucleosynthesis limit of $\sim 10^7$m. Neutral LLPs with lifetimes above $\sim$ 100m are particularly difficult to probe, as the sensitivity of the LHC main detectors is limited by challenging …
Search for point-like sources of ultra-high energy neutrinos at the pierre auger observatory and improved limit on the diffuse flux of tau neutrinos
2012
The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy Eν between 1017 eV and 1020 eV from point-like sources across the sky south of +55º and north of −65º declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth’s crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of ∼3.5 years of a full surface detector array for the Earth-skimming channel and ∼2 years…
Calculated solar-neutrino capture rate for a radiochemical 205Tl-based solar-neutrino detector
2020
Radiochemical experiments for low-energy solar-neutrino detection have been making headlines by exploiting the isotopes 37Cl and 71Ga. Such a very low-threshold measurement of this type can also be performed using 205Tl, which has been considered for decades for this purpose. A unique feature of this detector nucleus is the integration in the solar-neutrino flux over 106 of years owing to its long-living daughter 205Pb. In this Rapid Communication, we have calculated for the first time the cross section for the charged-current solar-neutrino scattering off 205Tl. Taking into account the solar-model-predicted neutrino fluxes and the electron-neutrino survival probabilities, a solar-neutrino …
Constraining the neutrino emission of gravitationally lensed Flat-Spectrum Radio Quasars with ANTARES data
2014
This paper proposes to exploit gravitational lensing effects to improve the sensitivity of neutrino telescopes to the intrinsic neutrino emission of distant blazar populations. This strategy is illustrated with a search for cosmic neutrinos in the direction of four distant and gravitationally lensed Flat-Spectrum Radio Quasars. The magnification factor is estimated for each system assuming a singular isothermal profile for the lens. Based on data collected from 2007 to 2012 by the ANTARES neutrino telescope, the strongest constraint is obtained from the lensed quasar B0218+357, providing a limit on the total neutrino luminosity of this source of 1.08×10^46 erg s-1. This limit is about one o…
Improved global fit to Non-Standard neutrino Interactions using COHERENT energy and timing data
2020
We perform a global fit to neutrino oscillation and coherent neutrino-nucleus scattering data, using both timing and energy information from the COHERENT experiment. The results are used to set model-independent bounds on four-fermion effective operators inducing non-standard neutral-current neutrino interactions. We quantify the allowed ranges for their Wilson coefficients, as well as the status of the LMA-D solution, for a wide class of new physics models with arbitrary ratios between the strength of the operators involving up and down quarks. Our results are presented for the COHERENT experiment alone, as well as in combination with the global data from oscillation experiments. We also q…
Effective Field Theories for heavy probes in a hot QCD plasma and in the early universe
2016
International audience; There are many interesting problems in heavy-ion collisions and in cosmology that involve the interaction of a heavy particle with a medium. An example is the dissociation of heavy quarkonium seen in heavy-ion collisions. This was believed to be due to the screening of chromoelectric fields that prevents the heavy quarks from binding, however in the last years several perturbative and lattice computations have pointed out to the possibility that dissociation is due to the finite lifetime of a quarkonium state inside the medium. Regarding cosmology, the study of the behavior of heavy Majorana neutrinos in a hot medium is important to understand if this model can expla…
Search for a diffuse flux of astrophysical muon neutrinos with the IceCube 59-string configuration
2013
A search for high-energy neutrinos was performed using data collected by the IceCube Neutrino Observatory from May 2009 to May 2010, when the array was running in its 59-string configuration. The data sample was optimized to contain muon neutrino induced events with a background contamination of atmospheric muons of less than 1%. These data, which are dominated by atmospheric neutrinos, are analyzed with a global likelihood fit to search for possible contributions of prompt atmospheric and astrophysical neutrinos, neither of which have yet been identified. Such signals are expected to follow a harder energy spectrum than conventional atmospheric neutrinos. In addition, the zenith angle dist…
Cornering (3+1) sterile neutrino schemes
2001
Using the most recent atmospheric neutrino data, as well as short-baseline, long-baseline and tritium $\beta$-decay data we show that the joint interpretation of the LSND, solar and atmospheric neutrino anomalies in (3+1) sterile neutrino schemes is severely disfavored, in contrast to the theoretically favored (2+2) schemes.
Cosmic microwave background constraints on secret interactions among sterile neutrinos
2017
Secret contact interactions among eV sterile neutrinos, mediated by a massive gauge boson $X$ (with $M_X \ll M_W$), and characterized by a gauge coupling $g_X$, have been proposed as a mean to reconcile cosmological observations and short-baseline laboratory anomalies. We constrain this scenario using the latest Planck data on Cosmic Microwave Background anisotropies, and measurements of baryon acoustic oscillations (BAO). We consistently include the effect of secret interactions on cosmological perturbations, namely the increased density and pressure fluctuations in the neutrino fluid, and still find a severe tension between the secret interaction framework and cosmology. In fact, taking i…
Recent Probes of Standard and Non-standard Neutrino Physics With Nuclei
2019
We review standard and non-standard neutrino physics probes that are based on nuclear measurements. We pay special attention on the discussion of prospects to extract new physics at prominent rare event measurements looking for neutrino-nucleus scattering, such as the coherent elastic neutrino-nucleus scattering (CE$\nu$NS) that may involve lepton flavor violation (LFV) in neutral-currents (NC). For the latter processes several appreciably sensitive experiments are currently pursued or have been planed to operate in the near future, like the COHERENT, CONUS, CONNIE, MINER, TEXONO, RED100, vGEN, Ricochet, NUCLEUS etc. We provide a thorough discussion on phenomenological and theoretical studi…