Do high-energy neutrinos travel faster than photons in a discrete space-time?

The recent OPERA measurement of high-energy neutrino velocity, once independently verified, implies new physics in the neutrino sector. We revisit the theoretical inconsistency of the fundamental high-energy cutoff attributing to quantum gravity with the parity-violating gauge symmetry of local quantum field theory describing neutrinos. This inconsistency suggests high-dimension operators of neutrino interactions. Based on these studies, we try to view the OPERA result, high-energy neutrino oscillations and indicate to observe the restoration of parity conservation by measuring the asymmetry of high-energy neutrinos colliding with left- and right-handed polarized electrons.Comment: revised version to appear in Phys. Lett. B. 13 pages and 2 figure

Phase Transition of Finite Size Quark Droplets with Isospin Chemical Potential in the Nanbu--Jona-Lasinio Model

Making use of the NJL model and the multiple reflection expansion pproximation, we study the phase transition of the finite size droplet with u and d quarks. We find that the dynamical masses of u, d quarks are different, and the chiral symmetry can be restored at different critical radii for u, d quark. It rovides a clue to understand the effective nucleon mass splitting in nuclear matter. Meanwhile, it shows that the maximal isospin chemical potential at zero temperature is much smaller than the mass of pion in free space.Comment: 12 pages, 3 figures. To appear in Physical Review

Non-spectator Contributions To The Lifetime of Λb\Lambda_{b}

In this work, we evaluate the contributions of non-spectator effects to the lifetimes of $\Lambda_b$ and B-mesons. Based on the well-established models and within a reasonable range of the concerned parameters, the contributions can reduce the lifetime of $\Lambda_b$ by $7 \sim 8$ compared to that of B-mesons which are not significantly affected. This might partly explain the measured ratio $\tau(\Lambda_{b})/\tau(B^{0})=0.79$ \cite{Data}, which has been a long-standing discrepancy between theory and experimental data

Investigation of the Surface Adhesion Phenomena and Mechanism of Gold-Plated Contacts at Superlow Making/Breaking Speed

Surface adhesion phenomena of gold-plated copper contact materials are studied in conditions of nonarc load (5/15/25 V and 0.2/0.5/1 A) and superlow speed (25 and 50 nm/s) realized by a piezoactuator during the making and breaking processes. It is shown that softening and melting of local asperities leads to interface adhesion, which results from the joule heat generated by the contact resistance; it is determined that the change of contact force with time obeys the negative exponential distribution and the time constant is associated with the adhesion force directly. Based on the fitting experimental data, the relationship between the adhesion force F z and the contact resistance R d while breaking can be expressed as F z ∝ R d -1 , which indicates that the main component of contact resistance is the bulk resistance of weld nugget and the constriction resistance is negligible

Natural constraints on the gluon-quark vertex

In principle, the strong-interaction sector of the Standard Model is characterised by a unique renormalisation-group-invariant (RGI) running interaction and a unique form for the dressed--gluon-quark vertex, $\Gamma_\mu$; but, whilst much has been learnt about the former, the latter is still obscure. In order to improve this situation, we use a RGI running-interaction that reconciles both top-down and bottom-up analyses of the gauge sector in quantum chromodynamics (QCD) to compute dressed-quark gap equation solutions with 1,660,000 distinct Ansaetze for $\Gamma_\mu$. Each one of the solutions is then tested for compatibility with three physical criteria and, remarkably, we find that merely 0.55% of the solutions survive the test. Plainly, therefore, even a small selection of observables places extremely tight bounds on the domain of realistic vertex Ansaetze. This analysis and its results should prove useful in constraining insightful contemporary studies of QCD and hadronic phenomena.Comment: 6 pages, 7 figure

Phase diagram and critical endpoint for strongly-interacting quarks

We introduce a method based on the chiral susceptibility, which enables one to draw a phase diagram in the chemical-potential/temperature plane for strongly-interacting quarks whose interactions are described by any reasonable gap equation, even if the diagrammatic content of the quark-gluon vertex is unknown. We locate a critical endpoint (CEP) at (\mu^E,T^E) ~ (1.0,0.9)T_c, where T_c is the critical temperature for chiral symmetry restoration at \mu=0; and find that a domain of phase coexistence opens at the CEP whose area increases as a confinement length-scale grows.Comment: 4 pages, 3 figure