اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدPerturbing neutrino oscillations around the solar resonance
104
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Atmospheric neutrinos at low energies, $E lsim 500$ MeV, is known to be a rich source of information of lepton mixing parameters. We formulate a simple perturbative framework to elucidate the characteristic features of neutrino oscillation at around the solar-scale enhancement due to the matter effect. The clearest message we could extract from our perturbation theory is that CP violation in the appearance oscillation probability is large, a factor of $sim 10$ times larger than CP violation at around the atmospheric-scale oscillation maximum. Underlying mechanism for it is that one of the suppression factors on the CP phase dependent terms due to smallness of $Delta m^2_{21} / Delta m^2_{31}$ are dynamically lifted by the solar-scale enhancement. Our framework has a unique feature as a perturbation theory in which large $Delta m^2_{31}$ term outside the key 1-2 sector for the solar-scale resonance does not yield sizeable corrections. On the contrary, the larger the $Delta m^2_{31}$, the smaller the higher order corrections.
قيم البحث
اقرأ أيضاً
The historical discovery of neutrino oscillations using solar and atmospheric neutrinos, and subsequent accelerator and reactor studies, has brought neutrino physics to the precision era. We note that CP effects in oscillation phenomena could be diff
icult to extract in the presence of unitarity violation. As a result upcoming dedicated leptonic CP violation studies should take into account the non-unitarity of the lepton mixing matrix. Restricting non-unitarity will shed light on the seesaw scale, and thereby guide us towards the new physics responsible for neutrino mass generation.
We examine scenarios in which a dark sector (dark matter, dark radiation, or dark energy) couples to the active neutrinos. For light and weakly-coupled exotic sectors we find that scalar, vector, or tensor dark backgrounds may appreciably impact neut
rino propagation while remaining practically invisible to all other phenomenological probes. The dark medium may induce small departures from the Standard Model predictions or even offer an alternative explanation of neutrino oscillations. While the propagation of neutrinos is affected in all experiments, atmospheric data currently represent the most promising probe of the new physics scale. We quantify the future sensitivity of the ORCA detector of KM3NeT and the IceCube experiment and find that all exotic effects can be constrained at the level of a few percent of the Earth matter potential, with couplings mediating $mu$-neutrino transitions being most constrained. Long baseline experiments like DUNE may provide additional complementary information on the scale of the dark sector.
We consider a solution of the atmospheric neutrino problem based on oscillations of muon neutrinos to sterile neutrinos: $ u_{mu}$ $leftrightarrow$ $ u_s$. The zenith angle ($Theta$) dependences of the neutrino and upward-going muon fluxes in presenc
e of these oscillations are studied. The dependences have characteristic form with two dips: at $cos Theta = -0.6 div -0.2$ and $cos Theta = -1.0 div -0.8$. The latter dip is due to parametric resonance in oscillations of neutrinos which cross the core of the earth. A comparison of predictions with data from the MACRO, Baksan and Super-Kamiokande experiments is given.
We consider a model where right-handed neutrinos propagate in a large compactified extra dimension, engendering Kaluza-Klein (KK) modes, while the standard model particles are restricted to the usual 4-dimensional brane. A mass term mixes the KK mode
s with the standard left-handed neutrinos, opening the possibility of change the 3 generation mixing pattern. We derive bounds on the maximum size of the extra dimension from neutrino oscillation experiments. We show that this model provides a possible explanation for the deficit of nu_e in Ga solar neutrino calibration experiments and of the anti-nu_e in short baseline reactor experiments.
At the previous Venice meeting NO-VE 2008, we discussed possible hints in favor of a nonzero value for the unknown neutrino mixing angle theta(13), emerging from the combination of solar and long-baseline reactor data, as well as from the combination
of atmospheric, CHOOZ and long-baseline accelerator nu_mu->nu_mu data. Recent MINOS 2009 results in the nu_mu->nu_e appearance channel also seem to support such hints. A combination of all current oscillation data provides, as preferred range, sin^2 theta(13) = 0.02 +- 0.01 (1sigma). We review several issues raised by such hints in the last year, and comment on their possible near-future improvements and tests.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
