Physics Potential of Long-Baseline Experiments

The discovery of neutrino mixing and oscillations over the past decade provides firm evidence for new physics beyond the Standard Model. Recently, theta13 has been determined to be moderately large, quite close to its previous upper bound. This represents a significant milestone in establishing the three-flavor oscillation picture of neutrinos. It has opened up exciting prospects for current and future long-baseline neutrino oscillation experiments towards addressing the remaining fundamental questions, in particular the type of the neutrino mass hierarchy and the possible presence of a CP-violating phase. Another recent and crucial development is the indication of non-maximal 2-3 mixing angle, causing the octant ambiguity of theta23. In this paper, I will review the phenomenology of long-baseline neutrino oscillations with a special emphasis on sub-leading three-flavor effects, which will play a crucial role in resolving these unknowns. First, I will give a brief description of neutrino oscillation phenomenon. Then, I will discuss our present global understanding of the neutrino mass-mixing parameters and will identify the major unknowns in this sector. After that, I will present the physics reach of current generation long-baseline experiments. Finally, I will conclude with a discussion on the physics capabilities of accelerator-driven possible future long-baseline precision oscillation facilities.Comment: 44 pages, 37 pdf figures, 5 tables. Review article to appear in Advances in High Energy Physic

Exploration prospects of a long baseline Beta Beam neutrino experiment with an iron calorimeter detector

A high intensity source of a single neutrino flavour with known spectrum is most desirable for precision measurements, the consensus direction for the future. The beta beam is an especially suitable option for this. We discuss the prospects of a very long baseline beta beam experiment with a magnetized iron calorimeter detector. In particular, with the source at CERN and the detector at the proposed India-based Neutrino Observatory (INO) the baseline is near the `magic' value where the effect of the CP phase is small. We observe that this experiment will be well suited to determine the sign of $m_3^2 - m_2^2$ and will be capable of probing $\theta_{13}$ down to about 1$^\circ$.Comment: 11 pages, 6 figures, Latex, more discussions added, version accepted in Phys. Lett.

Indirect searches of Galactic diffuse dark matter in INO-MagICAL detector

The signatures for the existence of dark matter are revealed only through its gravitational interaction. Theoretical arguments support that the Weakly Interacting Massive Particle (WIMP) can be a class of dark matter and it can annihilate and/or decay to Standard Model particles, among which neutrino is a favorable candidate. We show that the proposed 50 kt Magnetized Iron CALorimeter (MagICAL) detector under the India-based Neutrino Observatory (INO) project can play an important role in the indirect searches of Galactic diffuse dark matter in the neutrino and antineutrino mode separately. We present the sensitivity of 500 kt$\cdot$yr MagICAL detector to set limits on the velocity-averaged self-annihilation cross-section ($\langle\sigma v\rangle$) and decay lifetime ($\tau$) of dark matter having mass in the range of 2 GeV $\leq m_\chi \leq$ 90 GeV and 4 GeV $\leq m_\chi \leq$ 180 GeV respectively, assuming no excess over the conventional atmospheric neutrino and antineutrino fluxes at the INO site. Our limits for low mass dark matter constrain the parameter space which has not been explored before. We show that MagICAL will be able to set competitive constraints, $\langle\sigma v\rangle\leq 1.87\,\times\,10^{-24}$ cm$^3$ s$^{-1}$ for $\chi\chi\rightarrow\nu\bar\nu$ and $\tau\geq 4.8\,\times\,10^{24}$ s for $\chi\rightarrow\nu\bar\nu$ at 90$\%$ C.L. (1 d.o.f.) for $m_\chi$ = 10 GeV assuming the NFW as dark matter density profile.Comment: 28 pages, 22 pdf figures. Discussions & references added. Fig. 9 replaced with new figure for better understanding. Accepted in JHE

Probing Neutrino Oscillation Parameters using High Power Superbeam from ESS

A high-power neutrino superbeam experiment at the ESS facility has been proposed such that the source-detector distance falls at the second oscillation maximum, giving very good sensitivity towards establishing CP violation. In this work, we explore the comparative physics reach of the experiment in terms of leptonic CP-violation, precision on atmospheric parameters, non-maximal theta23, and its octant for a variety of choices for the baselines. We also vary the neutrino vs. the anti-neutrino running time for the beam, and study its impact on the physics goals of the experiment. We find that for the determination of CP violation, 540 km baseline with 7 years of neutrino and 3 years of anti-neutrino (7nu+3nubar) run-plan performs the best and one expects a 5sigma sensitivity to CP violation for 48% of true values of deltaCP. The projected reach for the 200 km baseline with 7nu+3nubar run-plan is somewhat worse with 5sigma sensitivity for 34% of true values of deltaCP. On the other hand, for the discovery of a non-maximal theta23 and its octant, the 200 km baseline option with 7nu+3nubar run-plan performs significantly better than the other baselines. A 5sigma determination of a non-maximal theta23 can be made if the true value of sin^2theta23 lesssim 0.45 or sin^2theta23 gtrsim 0.57. The octant of theta23 could be resolved at 5sigma if the true value of sin^2theta23 lesssim 0.43 or gtrsim 0.59, irrespective of deltaCP.Comment: 21 pages, 37 pdf figures, 3 tables. Sensitivities quoted at 3 and 5\sigma. Discussion on CP asymmetry added. Numerical methods discussed in detail. Some parts of the text rewritten. New references. Matches with published versio