118441255
OPERA SUPERLUMINAL NEUTRINOS AND KINEMATICS IN FINSLER SPACETIME
The OPERA collaboration recently reported that the muon neutrinos could be superluminal. More recently, Cohen and Glashow pointed that such superluminal neutrinos would be suppressed since they lose their energies rapidly via bremsstrahlung. Here, we propose that the Finslerian nature of the space time could account for the superluminal phenomena of particles. The Finsler spacetime permits the existence of the superluminal behavior of particles while the causality still holds. A new dispersion relation is obtained in a class of Finsler spacetimes. It is shown that the superluminal speed is linearly dependent on the energy per unit mass of the particle. We find that such a superluminal speed formula is consistent with the data of the OPERA, MINOS and Fermilab-1979 neutrino experiments as well as the observations on the neutrinos from the SN1987A.
119312663
Unification of Dark Matter and Dark Energy in a Modified Entropic Force Model
In Verlinde's entropic force scenario of gravity, Newton's laws and Einstein equations can be obtained from the first principles and general assumptions. However, the equipartition law of energy is invalid at very low temperatures. We show clearly that the threshold of the equipartition law of energy is related with horizon of the universe. Thus, a one-dimensional Debye (ODD) model in the direction of radius of the modified entropic force (MEF) may be suitable in description of the accelerated expanding universe. We present a Friedmann cosmic dynamical model in the ODD-MEF framework. We examine carefully constraints on the ODD-MEF model from the Union2 compilation of the Supernova Cosmology Project (SCP) collaboration, the data from the observation of the large-scale structure (LSS) and the cosmic microwave background (CMB), i.e. SNe Ia+LSS+CMB. The combined numerical analysis gives the best-fit value of the model parameters zeta similar or equal to 10(-9) and Omega(m0) = 0.224, with chi(2)(min) = 591.156. The corresponding age of the universe agrees with the result of D. Spergel et al. [J.M. Bardeen, B. Carter, and S.W. Hawking, Commun. Math. Phys. 31 (1973) 161] at 95% confidence level. The numerical result also yields an accelerated expanding universe without invoking any kind of dark energy. Taking zeta( 2 pi omega(D)/H-0) as a running parameter associated with the structure scale r, we obtain a possible unified scenario of the asymptotic flatness of the radial velocity dispersion of spiral galaxies, the accelerated expanding universe and the Pioneer 10/11 anomaly in the entropic force framework of Verlinde.
14722253
STATIC QUARK POTENTIAL AND THE RENORMALIZED ANISOTROPY ON TADPOLE IMPROVED ANISOTROPIC LATTICES
Static quark potential is studied using a tadpole improved gauge lattice action. The scale is set using the potential for a wide range of bare parameters. The renormalized anisotropy of the lattice is also measured.
2525683
Two particle states in an asymmetric box
The exact two-particle energy eigenstates in an asymmetric rectangular box with periodic boundary conditions in all three directions are studied. Their relation with the elastic scattering phases of the two particles in the continuum are obtained. These results can be viewed as a generalization of the corresponding formulae in a cubic box obtained by Luscher before. In particular, the s-wave scattering length is related to the energy shift in the finite box. Possible applications of these formulae are also discussed.
14104948
Two particle states in an asymmetric box and the elastic scattering phases
The exact two-particle energy eigenstates in a generic asymmetric rectangular box with periodic boundary conditions in all three directions are studied. Their relations with the elastic scattering phases of the two particles in the continuum are obtained for both ${D}_{4}$ and ${D}_{2}$ symmetries. These results can be viewed as a generalization of the corresponding formulas in a cubic box obtained by L\"uscher before. In particular, the s-wave scattering length is related to the energy shift in the finite box. Possible applications of these formulas are also discussed.
14726570
Massive domain wall fermions on four-dimensional anisotropic lattices
We formulate the massive domain wall fermions on anisotropic lattices. For the massive domain wall fermion, we find that the dispersion relation assumes the usual form in the low momentum region when the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. For light domain wall fermions, we verified that the chiral mode is stable against quantum fluctuations on anisotropic lattices. This calculation serves as a guidance for the tuning of the parameters in the quark action in future numerical simulations.
98875889
Isospin dependent global neutronnucleus optical model potential
Abstract In this paper, we construct a new phenomenological isospin dependent global neutron–nucleus optical model potential. Based on the existing experimental data of elastic scattering angular distributions for neutron as projectile, we obtain a set of the isospin dependent global neutron–nucleus optical model potential parameters, which can basically reproduce the experimental data for target nuclei from 24 Mg to 242 Pu with the energy region up to 200 MeV.
53695340
Exclusive radiative B-meson decays within the aligned two-Higgs-doublet model
A bstractIn the aligned two-Higgs-doublet model, the alignment of Yukawa matrices in flavour space guarantees the absence of tree-level flavour-changing neutral currents, while allowing at the same time for new sources of CP violation, implying potentially large effects in many low-energy processes. In this work we study the constraints from exclusive radiative B → V γ decays, where V denotes a light vector meson. The current experimental data on the CP-averaged branching ratios and the direct CP and isospin asymmetries are analyzed. It is found that, while the branching ratios and direct CP asymmetries do not constrain the parameter space much further compared to the inclusive B → Xs,d γ decays, complementary constraints can be obtained from the isospin asymmetries Δ(K*γ) and Δ(ργ). In addition, correlations between the various observables in exclusive B → V γ and inclusive B → Xs,d γ decays are investigated in detail, and predictions are made for several so far unmeasured observables.
119213789
$B \to K^{\ast} l^+ l^-$, $K l^+ l^-$ decays in a family non-universal $Z^{\prime}$ model
Motivated by the observed forward-backward asymmetry in $B\to K^{\ast} l^+ l^-$ decay, we perform a detailed analysis of this decay mode within a family non-universal $Z^{\prime}$ model. With the related coupling $Z^{\prime}-\bar{s}b$ constrained by $\bar{B}_s-B_s$ mixing, $B\to \pi K$, and $B\to X_s \mu^{+}\mu^{-}$ decays, we look for further constraint on the couplings $Z^{\prime}-\mu^{+}\mu^{-}$ from $A_{FB}(B\to K^{\ast} \mu^{+}\mu^{-})_{0 {\rm GeV}^2\leqslant q^2\leqslant 2 {\rm GeV}^2}$ and get numerically $B_{\mu\mu}^{L,R}\sim{\cal O}(10^{-2})$. Moreover, we find that the relations, $B_{\mu\mu}^{L}<B_{\mu\mu}^{R}$ and $B_{\mu\mu}^{L}+B_{\mu\mu}^{R}<0$, with a small negative $\phi_{s}^{L}$, are crucial to moderate the discrepancy for $A_{FB}(B\to K^{\ast} \mu^{+}\mu^{-})$ between the SM prediction and the experimental data. Numerically, comparing with the SM prediction, we find that $A_{FB}(B\to K^{\ast} \mu^{+}\mu^{-})_{0 {\rm GeV}^2\leqslant q^2\leqslant 2 {\rm GeV}^2}$ could be enhanced about 80% and 50% by $Z^{\prime}$ contribution at most in scenarios S1 and S2, corresponding to the two fitted results of $\phi_{s}$ by UTfit collaboration, respectively. However, the results are still about $1.5\sigma$ lower than the experimental measurement.
118637791
Topological orbital ladders
Synthetic quantum orbital materials, such as the recent double-well optical lattices loaded with s and p orbital atoms [1, 2], open an avenue to exploit symmetries beyond natural crystals. Exotic superfluid states were reported for bosons. Here, we unveil a topological phase of interacting fermions on a two-leg ladder of unequal parity orbitals, derived from the experimentally realized double-well lattices by dimension reduction. Z2 topological invariant originates simply from the staggered phases of sp-orbital quantum tunneling, requiring none of the previously known mechanisms such as spin-orbit coupling or artificial gauge field. Another unique feature is that upon crossing over to two dimensions with coupled ladders, the edge modes from each ladder form a parity-protected flat band at zero energy, opening the route to strongly correlated states controlled by interactions. Experimental signatures are found in density correlations and phase transitions to trivial band and Mott insulators. The uneven double-well potential formed by laser light has been developed into a powerful tool for quantum gases by numerous groups [1–6]. For instance, controls of atoms on the sand p-orbitals of the checkerboard [1] and hexagonal [6] optical lattices have been demonstrated, and correlation between these orbitals tends to give exotic quantum states [6, 7]. Motivated by these developments, we consider a lattice of uneven double-wells where fermionic atoms are loaded up to the sand porbital levels of the shallow and deep wells respectively, as shown in Fig. 1. The spatial symmetry of the orbital wave function dictates the complex hopping amplitudes between nearby sites. Under certain circumstances, as for the uneven double wells, the orbital hopping pattern is sufficient for producing topologically nontrivial band structures [8]. We will first focus on a one-dimensional ladder system illustrated in Fig. 1b and 1c. This corresponds to the quasi-one dimensional limit of a standard double-well optical lattice, with the optical potential given by
119180550
Anomalous tqZ coupling effects in rare B- and K-meson decays
A bstractAs a top-factory, the LHC is performing a direct study of top-quark anomalous FCNC couplings, which are, however, correlated closely with the rare B- and K-meson decays. In this paper, we study the effects of anomalous tqZ (with q = u, c) couplings in the rare decays Bs,d → μ+μ−, B → Xsν$ \overline \nu $, B → K(*)ν$ \overline \nu $, K+ → π+ν$ \overline \nu $, and KL → π0ν$ \overline \nu $. With the up-to-date experimental bounds on the branching ratios of these channels, constraints on the left-handed anomalous couplings $ X_{{ct}}^L $ and $ X_{{ut}}^L $ are derived, respectively. With these low-energy constraints taken into account, we find that, for real couplings $ X_{{ct}}^L $ and $ X_{{ut}}^L $, the indirect upper bounds on B(t → qZ) are much lower than that from the D0 collaboration, but are still compatible with the 5σ discovery potential of ATLAS with an integrated luminosity of 10 fb−1. With refined measurements to be available at the LHCb, the future super-B factories, the NA62 at CERN, and the KOTO at J-PARC, closer correlations between the t → qZ and the rare B- and K-meson decays are expected in the near future, which will be helpful for the searches of the top-quark FCNC decays at the LHC.