scholarly journals Nonunitary neutrino mixing in short and long-baseline experiments

2021 ◽  
Vol 104 (7) ◽  
Author(s):  
D. V. Forero ◽  
C. Giunti ◽  
C. A. Ternes ◽  
M. Tórtola
2011 ◽  
Vol 26 (32) ◽  
pp. 5261-5297 ◽  
Author(s):  
JUN WU ◽  
JIMMY A. HUTASOIT ◽  
DANIEL BOYANOVSKY ◽  
RICHARD HOLMAN

The dynamics of neutrino mixing and oscillations are studied directly in finite real time in a model that effectively describes charged current weak interactions. Finite time corrections to the S-matrix result for the appearance and disappearance probabilities are obtained. It is observed that these effects may be of the same order of the S-matrix result in long-baseline appearance experiments. We argue that fundamentally, the S-matrix is ill-suited to describe long-baseline events due to the fact that the neutrino is produced in an entangled state with the charged lepton, which can be disentangled by the measurement of the charged lepton near the production site. The appearance and disappearance far-detection process is described from the time evolution of this disentangled "collapsed" state, allowing us to establish the conditions under which factorization of detection rates emerges in long-baseline experiments. We also study the time evolution of the reduced density matrix and show explicitly how oscillations are manifest in the off-diagonal terms, i.e. coherences, as a result of a finite time analysis. Lastly, we study a model for the "GSI anomaly" by obtaining the time evolution of the population of parent and daughter particles directly in real time. We confirm that the decay rate of parent and growth rate of daughters do not feature oscillatory behavior from interference of mass eigenstates.


2003 ◽  
Vol 18 (22) ◽  
pp. 4039-4052 ◽  
Author(s):  
MILIND V. DIWAN

We analyze the prospects of a feasible, very long baseline neutrino oscillation experiment consisting of a conventional horn produced low energy wide band beam and a detector of 500 kT fiducial mass with modest requirements on event recognition and resolution. Such an experiment is intended primarily to measure CP invariance parameters in the neutrino sector. We analyze the sensitivity of such an experiment. The conclusion is that it will allow determination of the CP parameter δCP, if the currently unknown mixing parameter sin 22θ13 ≥ 0.01, a value about 10 times lower than the present experimental upper limit. Such an experiment has great potential for precise measurements of all parameters in the neutrino mixing matrix including [Formula: see text], sin 22θ23, [Formula: see text], and the mass ordering of neutrinos through the observation of the matter effect in the νμ → νe appearance channel.


2010 ◽  
Vol 81 (5) ◽  
Author(s):  
P. Adamson ◽  
C. Andreopoulos ◽  
D. J. Auty ◽  
D. S. Ayres ◽  
C. Backhouse ◽  
...  

Author(s):  
C.R. Das ◽  
Jukka Maalampi ◽  
João Pulido ◽  
Sampsa Vihonen

We study the possibility of determining the octant of the neutrino mixing angle 23, that is, whether 23 > 45 or 23 < 45, in long baseline neutrino experiments. Here we numerically derived the sensitivity limits within which these experiments can determine, by measuring the probability of the ! e transitions, the octant of 23 with a 5 certainty. The interference of the CP violation angle with these limits, as well as the effects of the baseline length and the run-time ratio of neutrino and antineutrino modes of the beam have been analyzed.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Kalpana Bora ◽  
Gayatri Ghosh ◽  
Debajyoti Dutta

In a recent work by us, we have studied how CP violation discovery potential can be improved at long baseline neutrino experiments (LBNE/DUNE), by combining with its ND (near detector) and reactor experiments. In this work, we discuss how this study can be further analysed to resolve entanglement of the quadrant of leptonic CPV phase and octant of atmospheric mixing angleθ23, at LBNEs. The study is done for both NH (normal hierarchy) and IH (inverted hierarchy), HO (higher octant), and LO (lower octant). We show how baryogenesis can enhance the effect of resolving this entanglement and how possible values of the leptonic CP violating phaseδCPcan be predicted in this context. With respect to the latest global fit data of neutrino mixing angles, we predict the values ofδCPfor different cases. In this context we present favoured values ofδCP(δCPrange at ≥2σ) constrained by the latest updated BAU range and also confront our predictions ofδCPwith an up-to-date global analysis of neutrino oscillation data. We find that some region of the favouredδCPparameter space lies within the best fit values aroundδCP≃1.3π–1.4π. A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in this framework within the nonsupersymmetric SO(10)models.


2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Sandhya Choubey ◽  
Debajyoti Dutta ◽  
Dipyaman Pramanik

AbstractActive-sterile neutrino mixing is known to affect the neutrino oscillation probabilities at both short as well as long-baselines. In particular, constraints on active-sterile neutrino oscillation parameters can be obtained from long-baseline experiments such as T2HK and DUNE. We present here existence of fake solution in the appearance channel for the 3 + 1 scenario at long-baseline experiments. We show that the appearance probability is same for values of $$\Delta m_{41}^2$$Δm412 for which the fast oscillations are averaged out and for $$\Delta m_{41}^2=(1/2)\Delta m_{31}^2$$Δm412=(1/2)Δm312. The fake solution does not appear for the disappearance channel.


2013 ◽  
Vol 2013 ◽  
pp. 1-34 ◽  
Author(s):  
Soo-Bong Kim ◽  
Thierry Lasserre ◽  
Yifang Wang

We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very recently the most precise determination of the neutrino mixing angleθ13. This paper provides an overview of the upcoming experiments and of the projects under development, including the determination of the neutrino mass hierarchy and the possible use of neutrinos for society, for nonproliferation of nuclear materials, and geophysics.


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