T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Izmaylov, A., Sorel, M., & Stamoulis, P. (2016). Measurement of the muon neutrino inclusive charged-current cross section in the energy range of 1-3 GeV with the T2K INGRID detector. Phys. Rev. D, 93(7), 072002–23pp.
Abstract: We report a measurement of the nu(mu)-nucleus inclusive charged-current cross section (= sigma(cc)) on iron using data from the INGRID detector exposed to the J-PARC neutrino beam. The detector consists of 14 modules in total, which are spread over a range of off-axis angles from 0 degrees to 1.1 degrees. The variation in the neutrino energy spectrum as a function of the off-axis angle, combined with event topology information, is used to calculate this cross section as a function of neutrino energy. The cross section is measured to be sigma(cc) (1.1 GeV) = 1.10 +/- 0.15 (10(-38) cm(2)/nucleon), sigma(cc) (2.0 GeV) = 2.07 +/- 0.27 (10(-38) cm(2)/nucleon), and sigma(cc) (3.3 GeV) = 2.29 +/- 0.45 (10(-38) cm(2)/nucleon), at energies of 1.1, 2.0, and 3.3 GeV, respectively. These results are consistent with the cross section calculated by the neutrino interaction generators currently used by T2K. More importantly, the method described here opens up a new way to determine the energy dependence of neutrino-nucleus cross sections.
|
Di Valentino, E., Gariazzo, S., Gerbino, M., Giusarma, E., & Mena, O. (2016). Dark radiation and inflationary freedom after Planck 2015. Phys. Rev. D, 93(8), 083523–28pp.
Abstract: The simplest inflationary models predict a primordial power spectrum (PPS) of the curvature fluctuations that can be described by a power-law function that is nearly scale invariant. It has been shown, however, that the low-multipole spectrum of the cosmic microwave background anisotropies may hint at the presence of some features in the shape of the scalar PPS, which could deviate from its canonical power-law form. We study the possible degeneracies of this nonstandard PPS with the active neutrino masses, the effective number of relativistic species, and a sterile neutrino or a thermal axion mass. The limits on these additional parameters are less constraining in a model with a nonstandard PPS when including only the temperature autocorrelation spectrum measurements in the data analyses. The inclusion of the polarization spectra noticeably helps in reducing the degeneracies, leading to results that typically show no deviation from the Lambda CDM model with a standard power-law PPS. These findings are robust against changes in the function describing the noncanonical PPS. Albeit current cosmological measurements seem to prefer the simple power-law PPS description, the statistical significance to rule out other possible parametrizations is still very poor. Future cosmological measurements are crucial to improve the present PPS uncertainties.
|
Sun, Z. F., & Vicente Vacas, M. J. (2016). Masses of doubly charmed baryons in the extended on-mass-shell renormalization scheme. Phys. Rev. D, 93(9), 094002–8pp.
Abstract: In this work, we investigate the mass corrections of the doubly charmed baryons up to (NLO)-L-2 in the extended-on-mass-shell (EOMS) renormalization scheme, comparing with the results of heavy baryon chiral perturbation theory. We find that the terms from the heavy baryon approach are a subset of those obtained in the EOMS scheme. By fitting the lattice data, we can determine the parameters (m) over tilde, alpha, c(1) and c(7) from the Lagrangian, while in the heavy baryon approach no information on c(1) can be obtained from the baryons mass. Correspondingly, the masses of m(Xi cc) and m(Omega cc) are predicted, in the EOMS scheme, extrapolating the results from different values of the charm quark and the pion masses of the lattice QCD calculations.
|
Wang, E., Chen, H. X., Geng, L. S., Li, D. M., & Oset, E. (2016). Hidden-charm pentaquark state in Lambda(0)(b) -> J/psi p pi(-) decay. Phys. Rev. D, 93(9), 094001–10pp.
Abstract: We study here the A(b)(0) -> J/psi p pi(-) reaction in analogy to the A(b)(0) -> J/psi pK(-) one, and we note that in both decays there is a sharp structure (dip or peak) in the J/psi p mass distribution around 4450 MeV, which is associated in the A(b)(0) -> J/psi pK(-) experiment to an exotic pentaquark baryonic state, although in J/psi p pi(-) it shows up with relatively low statistics. We analyze the A(b)(0) -> J/psi p pi(-) interaction along the same lines as the A(b)(0) -> J/psi pK(-) one, with the main difference stemming from the reduced Cabibbo strength in the former and the consideration of the pi(-)p final state interaction instead of the K(-)p one. We find that with a minimal input, introducing the pi(-)p and J/psi p interaction in S-wave with realistic interactions, and the empirical P-wave and D-wave contributions, one can accomplish a qualitative description of the pi(-)p and J/psi p mass distributions. More importantly, the peak structure followed by a dip of the experimental J/psi p mass distribution is reproduced with the same input as used to describe the data of A(b)(0) -> J/psi pK(-) reaction. The repercussion for the triangular singularity mechanism, invoked in some works to explain the pentaquark peak, is discussed.
|
Bonilla, C., Nebot, M., Valle, J. W. F., & Srivastava, R. (2016). Flavor physics scenario for the 750 GeV diphoton anomaly. Phys. Rev. D, 93(7), 073009–5pp.
Abstract: A simple variant of a realistic flavor symmetry scheme for fermion masses and mixings provides a possible interpretation of the diphoton anomaly as an electroweak singlet “flavon.” The existence of TeV scale vectorlike T-quarks required to provide adequate values for Cabibbo-Kobayashi-Maskawa (CKM) parameters can also naturally account for the diphoton anomaly. Correlations between V-ub and V-cb with the vectorlike T-quark mass can be predicted. Should the diphoton anomaly survive in a future run, our proposed interpretation can also be tested in upcoming B and LHC studies.
|
