530 research outputs found
Right-handed Dirac Neutrinos in Scattering and Azimuthal Asymmetry in Recoil Electron Event Rates
In this paper a scenario with the participation of the exotic scalar S,
tensor T and pseudoscalar couplings of the right-handed neutrinos in addition
to the standard vector V, axial A couplings of the left-handed neutrinos in the
low-energy and scattering processes is
considered. Neutrinos are assumed to be massive Dirac fermions and to be
polarized. Both reactions are studied at the level of the four-fermion point
interaction. The main goal is to show that the physical consequence of the
presence of the right-handed neutrinos is an appearance of the azimuthal
asymmetry in the angular distribution of the recoil electrons caused by the
non-vanishing interference terms between the standard and exotic couplings,
proportional to the transverse neutrino polarization vector. The upper limits
on the expected effect of this asymmetry for the low-energy neutrinos are found. We also show that if the neutrino helicity rotation
in the solar magnetic field takes place, the similar
effect of the azimuthal asymmetry of the recoil electrons scattered by the
solar neutrinos should be observed. This effect would also come from the
interference terms between the standard and exotic
couplings. New-type neutrino detectors with good angular resolution could
search for the azimuthal asymmetry in event number.Comment: EPJ C style, 14 pages, 5 eps figures; to appear in Eur. Phys. J
Thermal neutrinos from pre-supernova
We would like to discuss prospects for neutrino observations of the
core-collapse supernova progenitor during neutrino-cooled stage. We will
present new theoretical results on thermal neutrino and antineutrino spectra
produced deep inside the pre-supernova core. Three competing processes: pair-,
photo and plasma-neutrino production, are taken into account. The results will
be used to estimate signal in existing and future neutrino detectors. Chance
for supernova prediction is estimated, with possible aid to core-collapse
neutrino and gravitational wave detectors in the form of early warning.Comment: 1 page, Contribution to the Proceedings of Neutrino 2006 Conferenc
GPS-based CERN-LNGS time link for Borexino
We describe the design, the equipment, and the calibration of a new GPS based
time link between CERN and the Borexino experiment at the Gran Sasso Laboratory
in Italy. This system has been installed and operated in Borexino since March
2012, and used for a precise measurement of CNGS muon neutrinos speed in May
2012. The result of the measurement will be reported in a different letter.Comment: 13 pages, 11 figure
Scattering of neutrinos on a polarized electron target as a test for new physics beyond the Standard Model
In this paper, we analyze the scattering of the neutrino beam on the
polarized electron target, and predict the effects of two theoretically
possible scenarios beyond the Standard Model. In both scenarios, Dirac
neutrinos are assumed to be massive.
First, we consider how the existence of CP violation phase between the
complex vector V and axial A couplings of the Left-handed neutrinos affects the
azimuthal dependence of the differential cross section. The future superbeam
and neutrino factory experiments will provide the unique opportunity for the
leptonic CP violation studies, if the large magnetized sampling calorimeters
with good event reconstruction capabilities are build.
Next, we take into account a scenario with the participation of the exotic
scalar S coupling of the Right-handed neutrinos in addition to the standard
vector V and axial A couplings of the Left-handed neutrinos. The main goal is
to show how the presence of the R-handed neutrinos, in the above process
changes the spectrum of recoil electrons in relation to the expected Standard
Model prediction, using the current limits on the non-standard couplings. The
interference terms between the standard and exotic couplings in the
differential cross section depend on the angle between the transverse
incoming neutrino polarization and the transverse electron polarization of the
target, and do not vanish in the limit of massless neutrino. The detection of
the dependence on this angle in the energy spectrum of recoil electrons would
be a signature of the presence of the R-handed neutrinos in the
neutrino-electron scattering. To make this test feasible, the polarized
artificial neutrino source needs to be identified.Comment: 11 pages, 3 eps figures, revtex, submitted to publicatio
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