Search results for "nuclear physics"
showing 10 items of 5307 documents
Sterile neutrinos or flux uncertainties? — Status of the reactor anti-neutrino anomaly
2017
The $\sim 3\sigma$ discrepancy between the predicted and observed reactor anti-neutrino flux, known as the reactor anti-neutrino anomaly, continues to intrigue. The recent discovery of an unexpected bump in the reactor anti-neutrino spectrum, as well as indications that the flux deficit is different for different fission isotopes seems to disfavour the explanation of the anomaly in terms of sterile neutrino oscillations. We critically review this conclusion in view of all available data on electron (anti)neutrino disappearance. We find that the sterile neutrino hypothesis cannot be rejected based on global data and is only mildly disfavored compared to an individual rescaling of neutrino fl…
If sterile neutrinos exist, how can one determine the total solar neutrino fluxes?
2002
The 8B solar neutrino flux inferred from a global analysis of solar neutrino experiments is within 11% (1 sigma) of the predicted standard solar model value if only active neutrinos exist, but could be as large as 1.7 times the standard prediction if sterile neutrinos exist. We show that the total 8B neutrino flux (active plus sterile neutrinos) can be determined experimentally to about 10% (1 sigma) by combining charged current measurements made with the KamLAND reactor experiment and with the SNO CC solar neutrino experiment, provided the LMA neutrino oscillation solution is correct and the simulated performance of KamLAND is valid. Including also SNO NC data, the sterile component of the…
Four-neutrino oscillation solutions of the solar neutrino problem
2000
We present an analysis of the neutrino oscillation solutions of the solar neutrino problem in the framework of four-neutrino mixing where a sterile neutrino is added to the three standard ones. We perform a fit to the full data set corresponding to the 825-day Super-Kamiokande data sample as well as to Chlorine, GALLEX and SAGE and Kamiokande experiments. In our analysis we use all measured total event rates as well as all Super-Kamiokande data on the zenith angle dependence and the recoil electron energy spectrum. We consider both transitions via the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism as well as oscillations in vacuum (just-so) and find the allowed solutions for different values …
A search for neutrino–antineutrino mass inequality by means of sterile neutrino oscillometry
2015
The investigation of the oscillation pattern induced by the sterile neutrinos might determine the oscillation parameters, and at the same time, allow to probe CPT symmetry in the leptonic sector through neutrino-antineutrino mass inequality. We propose to use a large scintillation detector like JUNO or LENA to detect electron neutrinos and electron antineutrinos from MCi electron capture or beta decay sources. Our calculations indicate that such an experiment is realistic and could be performed in parallel to the current research plans for JUNO and RENO. Requiring at least 5$\sigma$ confidence level and assuming the values of the oscillation parameters indicated by the current global fit, w…
Heavy neutrino searches at the lhc with displaced vertices
2013
Sterile neutrinos with masses in the range (1-100) GeV, have been searched for in a variety of experiments. Here, we discuss the prospects to search for sterile neutrinos at the LHC using displaced vertices. Two different cases are discussed: (i) the standard model extended with sterile neutrinos and (ii) right-handed neutrinos in a left-right symmetric extension of the standard model. A dedicated displaced vertex search will allow to probe parts of the parameter space not accessible to other searches, but will require large luminosity in both cases.
Impact of squark generation mixing on the search for squarks decaying into fermions at LHC
2010
We study the effect of squark generation mixing on squark production and decays at LHC in the Minimal Supersymmetric Standard Model (MSSM). We show that the effect can be very large despite the very strong constraints on quark flavour violation (QFV) from experimental data on B mesons. We find that the two lightest up-type squarks su_{1,2} can have large branching ratios for the decays into 'c-quark + neutralino_1' and 't-quark + neutralino_1' at the same time due to squark generation mixing, leading to QFV signals 'pp -> c bar{t} (t bar{c}) + missing-E_T + X' with a significant rate. The observation of this remarkable signature would provide a powerful test of supersymmetric QFV at LHC.…
A precision measurement of charm dimuon production in neutrino interactions from the NOMAD experiment
2013
We present our new measurement of the cross-section for charm dimuon production in neutrino iron interactions based upon the full statistics collected by the NOMAD experiment. After background subtraction we observe 15 344 charm dimuon events, providing the largest sample currently available. The analysis exploits the large inclusive charged current sample - about 9 x 10(6) events after all analysis cuts - and the high resolution NOMAD detector to constrain the total systematic uncertainty on the ratio of charm dimuon to inclusive Charged Current (CC) cross-sections to similar to 2%. We also perform a fit to the NOMAD data to extract the charm production parameters and the strange quark sea…
Water-cooled Pb–17Li test blanket module for ITER: Impact of the structural material grade on the neutronic responses
1998
Abstract The Water-Cooled Lithium Lead (WCLL) DEMO blanket is one of the two EU lines to be further developed with the aim of manufacturing by 2010 a Test Blanket Module for ITER (TBM). In this paper results of a 3D-Monte Carlo neutronic analysis of the TBM design are reported. A fully 3D heterogeneous model of the WCLL–TBM has been inserted into an existing ITER model accounting for a proper D–T neutron source. The structural material assumed for the calculations was martensitic 9% Cr steel code named Z 10 CDV Nb 9-1. Results have been compared with those obtained using MANET. The main nuclear responses of the TBM have been determined, such as detailed power deposition density, material da…
First spatial isotopic separation of relativistic uranium projectile fragments
1994
Abstract Spatial isotopic separation of relativistic uranium projectile fragments has been achieved for the first time. The fragments were produced in peripheral nuclear collisions and spatially separated in-flight with the fragment separator FRS at GSI. A two-fold magnetic-rigidity analysis was applied exploiting the atomic energy loss in specially shaped matter placed in the dispersive central focal plane. Systematic investigations with relativistic projectiles ranging from oxygen up to uranium demonstrate that the FRS is a universal and powerful facility for the production and in-flight separation of monoisotopic, exotic secondary beams of all elements up to Z = 92. This achievement has …
Measurements of the top-quark mass using charged particle tracking
2010
21 páginas, 13 figuras, 6 tablas.-- PACS numbers: 12.15.-y, 13.85.-t, 14.60.-z, 14.65.Fy.-- CDF Collaboration: et al.