119286657
Getting the Best Out of T2K and NOvA
We explore the combined physics potential of T2K and NOvA in light of the moderately large measured value of theta13. For sin^2 2*theta13 = 0.1, which is close to the best fit value, a 90% C.L. evidence for the hierarchy can be obtained only for the combinations (Normal hierarchy, -170 <= deltaCP <= 0) and (Inverted hierarchy, 0 <= deltaCP <= 170), with the currently planned runs of NOvA and T2K. However, the hierarchy can essentially be determined for any value of deltaCP, if the statistics of NOvA are increased by 50% and those of T2K are doubled. Such an increase will also give an allowed region of deltaCP around its true value, except for the CP conserving cases deltaCP = 0 or 180. We demonstrate that any measurement of deltaCP is not possible without first determining hierarchy. We find that comparable data from a shorter baseline (L ~ 130 km) experiment will not lead to any significant improvement.
54179658
Exploring the three flavor effects with future superbeams using liquid argon detectors
A bstractRecent measurement of a moderately large value of θ13 signifies an important breakthrough in establishing the standard three flavor oscillation picture of neutrinos. It has provided an opportunity to explore the sub-dominant three flavor effects in present and future long-baseline experiments. In this paper, we perform a comparative study of the physics reach of two future superbeam facilities, LBNE and LBNO in their first phases of run, to resolve the issues of neutrino mass hierarchy, octant of θ23, and leptonic CP violation. We also find that the sensitivity of these future facilities can be improved significantly by adding the projected data from T2K and NOνA. Stand-alone LBNO setup with a 10 kt detector has a mass hierarchy discovery reach of more than 7σ, for the lowest allowed value of sin2θ23(true) = 0.34. This result is valid for any choice of true δCP and hierarchy. LBNE10, in combination with T2K and NOνA, can achieve 3σ hierarchy discrimination for any choice of δCP, sin2θ23, and hierarchy. The same combination can provide a 3σ octant resolution for sin2θ23(true) ≤ 0.44 or for sin2θ23(true) ≥ 0.58 for all values of δCP(true). LBNO can give similar results with 10 kt detector mass. In their first phases, both LBNE10 and LBNO with 20 kt detector can establish leptonic CP violation for around 50% values of true δCP at 2σ confidence level. In case of LBNE10, CP coverage at 3σ can be enhanced from 3% to 43% by combining T2K and NOνA data, assuming sin2θ23(true) = 0.5. For LBNO setup, CP violation discovery at 3σ is possible for 46% values of true δCP if we add the data from T2K and NOνA.
165892603
Getting the best out of T2K and NOvA
119769995
Physics Potential of a 2540 Km Baseline Superbeam Experiment
We study the physics potential of a neutrino superbeam experiment with a 2540 km baseline. We assume a neutrino beam similar to the NuMI beam in the medium energy configuration. We consider a 100 kton totally active scintillator detector at a 7 mr off‐axis location. We find that such a configuration has an outstanding hierarchy discriminating capability. In conjunction with the data from the present reactor neutrino experiments, it can determine the neutrino mass hierarchy at the 3σ level in less than 5 years, if sin22θ13≥0.01, running in the neutrino mode alone. As a stand alone experiment, with a 5 year neutrino run and a 5 year anti‐neutrino run, it can determine non‐zero θ13 at the 3σ level if sin2 2θ13≥7×10−3 and hierarchy at the 3σ level if sin22θ13≥8×10−3. This data can also distinguish δCP = π/2 from the CP conserving values of 0 and π, for sin22θ13≥0.02.
39175250
Neutrino mass hierarchy and octant determination with atmospheric neutrinos.
The recent discovery by the Daya-Bay and RENO experiments, that θ(13) is nonzero and relatively large, significantly impacts existing experiments and the planning of future facilities. In many scenarios, the nonzero value of θ(13) implies that θ(23) is likely to be different from π/4. Additionally, large detectors will be sensitive to matter effects on the oscillations of atmospheric neutrinos, making it possible to determine the neutrino mass hierarchy and the octant of θ(23). We show that a 50 kT magnetized liquid argon neutrino detector can ascertain the mass hierarchy with a significance larger than 4σ with moderate exposure times, and the octant at the level of 2-3σ with greater exposure.
119115506
High-precision measurement of atmospheric mass-squared splitting with T2K and NOvA
A precise measurement of the atmospheric mass-squared splitting |\Delta m^2_{\mu\mu}| is crucial to establish the three-flavor paradigm and to constrain the neutrino mass models. In addition, a precise value of |\Delta m^2_{\mu\mu}| will significantly enhance the hierarchy reach of future medium-baseline reactor experiments like JUNO and RENO-50. In this work, we explore the precision in |\Delta m^2_{\mu\mu}| that will be available after the full runs of T2K and NOvA. We find that the combined data will be able to improve the precision in |\Delta m^2_{\mu\mu}| to sub-percent level for maximal 2-3 mixing. Depending on the true value of \sin^2\theta_{23} in the currently-allowed 3 sigma range, the precision in |\Delta m^2_{\mu\mu}| will vary from 0.87% to 1.24%. We further demonstrate that this is a robust measurement as it remains almost unaffected by the present uncertainties in \theta_{13}, \delta_{CP}, the choice of mass hierarchy, and the systematic errors.
119180335
A note on CFT correlators in three dimensions
A bstractIn this note we present a simple method of constructing general conformally invariant three point functions of operators of various spins in three dimensions. Upon further imposing current conservation conditions, we find new parity violating structures for the three point functions involving either the stress-energy tensor, spin one currents, or higher spin currents. We find that all parity preserving structures for conformally invariant three point functions of higher spin conserved currents can be realized by free fields, whereas there is at most one parity violating structure for three point functions for each set of spins, which is not realized by free fields.
118340854
Chern–Simons theory with vector fermion matter
We study three-dimensional conformal field theories described by U(N) Chern–Simons theory at level k coupled to massless fermions in the fundamental representation. By solving a Schwinger–Dyson equation in light-cone gauge, we compute the exact planar free energy of the theory at finite temperature on ℝ2 as a function of the ’t Hooft coupling λ=N/k. Employing a dimensional reduction regularization scheme, we find that the free energy vanishes at |λ|=1; the conformal theory does not exist for |λ|>1. We analyze the operator spectrum via the anomalous conservation relation for higher spin currents, and in particular show that the higher spin currents do not develop anomalous dimensions at leading order in 1/N. We present an integral equation whose solution in principle determines all correlators of these currents at leading order in 1/N and present explicit perturbative results for all three-point functions up to two loops. We also discuss a light-cone Hamiltonian formulation of this theory where a W∞ algebra arises. The maximally supersymmetric version of our theory is ABJ model with one gauge group taken to be U(1), demonstrating that a pure higher spin gauge theory arises as a limit of string theory.
118570342
Holography of charged dilaton black holes
We study charged dilaton black branes in AdS4. Our system involves a dilaton ϕ coupled to a Maxwell field Fμν with dilaton-dependent gauge coupling, $ \frac{1}{{{g^2}}} = {f^2}\left( \phi \right) $. First, we find the solutions for extremal and near extremal branes through a combination of analytical and numerical techniques. The near horizon geometries in the simplest cases, where f(ϕ) = eαϕ, are Lifshitz-like, with a dynamical exponent z determined by α. The black hole thermodynamics varies in an interesting way with α, but in all cases the entropy is vanishing and the specific heat is positive for the near extremal solutions. We then compute conductivity in these backgrounds. We find that somewhat surprisingly, the AC conductivity vanishes like ω2 at T = 0 independent of α. We also explore the charged black brane physics of several other classes of gauge-coupling functions f(ϕ). In addition to possible applications in AdS/CMT, the extremal black branes are of interest from the point of view of the attractor mechanism. The near horizon geometries for these branes are universal, independent of the asymptotic values of the moduli, and describe generic classes of endpoints for attractor flows which are different from AdS2 × R2.