arXiv subjects

Takayuki Matsuki

Publications and source records attributed to Takayuki Matsuki.

82 records · Page 5Linked to original sources

arXiv2007

Radial Excitations of Heavy Mesons

Recent discovery of D_s states suggests existence of radial excitations. Our semirelativistic quark potential model succeeds in reproducing these staes within one to two percent of accuracy compared with the experiments, D_s0(2860) and D_s^*(2715), which are identified as 0^+ and 1^- radial excitations (n=2). We also present calculations of radial excitations for B/B_s heavy mesons. Relation between our formulation and the modified Goldberger-Treiman relation is also described.

hep-ph↗

arXiv2007

New Heavy-Light Mesons $Q\bar q$

We succeed in reproducing the $\ell=1$ $B$ mesons, $B_1(5720)$, $B_2^*(5745)$, and $B_{s2}^*(5839)$ that are recently reported by D0 and CDF, by using our semirelativistic quark potentila model, which also succeeded in predicting the mass spectra of the narrow $D_{sJ}$ as well as broad $D_0^*(0^+)$ and $D_1'(1^+)$ particles a couple of years ago. Mass of higher excited states ($\ell=1, 2$) of $B$ and $B_s$ mesons, which are not yet observed, is also predicted at the first order in $p/m_b$. We find the corresponding $B_{sJ}$ are below $BK/B^*K$ threshold and should have narrow decay widths contrary to most other predictions. Also already established states ($\ell=0$ and $\ell=1$) of $D$, $D_s$, $B$, and $B_s$ heavy mesons are simultaneously reproduced in good agreement with experimental data within one percent of accuracy. To calculate these $D/D_s$ and $B/B_s$ heavy mesons we use different values of strong coupling $α_s$ which conforms to a notion of running coupling.

hep-ph↗

arXiv2006

Model independent approach to studies of the confining dual Abrikosov vortex in SU(2) lattice gauge theory

We address the problem of determining the type I, type II or borderline dual superconductor behavior in maximal Abelian gauge SU(2) through the study of the dual Abrikosov vortex. We find that significant electric currents in the simulation data call into question the use of the dual Ginzburg Landau Higgs model in interpreting the data. Further, two definitions of the penetration depth parameter take two different values. The splitting of this parameter into two is intricately connected to the existence of electric currents. It is important in our approach that we employ definitions of flux and electric and magnetic currents that respect Maxwell equations exactly for lattice averages independent of lattice spacings. Applied to specific Wilson loop sizes, our conclusions differ from those that use the dual GLH model.

hep-lat↗

arXiv2003

Consistency of lattice definitions of U(1) flux in Abelian projected SU(2) gauge theory

We reexamine the dual Abrikosov vortex under the requirement that the lattice averages of the fields satisfy exact Maxwell equations [ME]. The electric ME accounts for the total flux and the magnetic ME determines the shape of the confining string. This leads to unique and consistent definitions of flux and electric and magnetic currents at finite lattice spacing. The resulting modification of the standard DeGrand-Toussaint construction gives a magnetic current comprised of smeared monopoles.

hep-lat↗

arXiv2003

Consistent Definitions of Flux and Electric and Magnetic Current in Abelian Projected SU(2) Lattice Gauge Theory

Through the use of a lattice U(1) Ward-Takahashi identity, one can find a precise definition of flux and electric four-current that does not rely on the continuum limit. The magnetic four-current defined for example by the DeGrand-Toussaint construction introduces order a^2 errors in the field distributions. We advocate using a single definition of flux in order to be consistent with both the electric and magnetic Maxwell's equations at any lattice spacing. In a U(1) theory the monopoles are slightly smeared by this choice, i.e. are no longer associated with a single lattice cube. In Abelian projected SU(2) the consistent definition suggests further modifications. For simulations in the scaling window, we do not foresee large changes in the standard analysis of the dual Abrikosov vortex in the maximal Abelian gauge because the order a^2 corrections have small fluctuations and tend to cancel out. However in other gauges, the consequences of our definitions could lead to large effects which may help in understanding the choice of gauge. We also examine the effect of truncating all monopoles except for the dominant cluster on the profile of the dual Abrikosov vortex.

hep-lat↗

arXiv2002

Dual Abrikosov vortex between confined charges

We show that the dual Abrikosov vortex between quark and antiquark in Abelian Projected SU(2) gauge theory is insensitive to truncation of all loops except the large monopole cluster noted by Hart and Teper. As the transverse distance increases, the discrepancy decreases, suggesting that the London penetration depth determined by the tail is invariant under the truncation of short loops.

hep-lat↗

arXiv2000

Gauge Symmetry Breakdown due to Dyanamical versus Elementary Higgs

We study in details on how gauge bosons can acquire mass when the chiral symmetry dynamically breaks down for massless gauge theory without scalars. Introducing dynamical scalar fields into the original gauge theory, we show that when the chiral symmetry breaks down, the theory gives gauge boson masses different from what would be obatained if an elemetary Higgs is included. We clarify the reason and propose one method how to calculate gauge boson masses in the case of dynamical gauge symmtry breakdown. We explain the method by using an example in which SU(5) massless gauge theory breaks down to SU(4) with massless fermions in appropriate representations.

hep-th↗

arXiv1997

Spectroscopy of Heavy Mesons Expanded in 1/m_Q

Operating just once with the naive Foldy-Wouthuysen-Tani transformation on the relativistic Fermi-Yang equation for $Q\bar q$ bound states described by the semi-relativistic Hamiltonian which includes Coulomb-like as well as confining scalar potentials, we have calculated heavy meson mass spectra of D and B together with higher spin states. Based on the formulation recently proposed, their masses and wave functions are expanded up to the second order in $1/m_Q$ with a heavy quark mass $m_Q$ and the lowest order equation is examined carefully to obtain a complete set of eigenfunctions for the Schrödinger equation. Heavy quark effective theory parameters, $\barΛ$, $λ_1$, and $λ_2$, are also determined at the first and second order in $1/m_Q$.

hep-ph↗

arXiv1995

Schrödinger Equation for Heavy Mesons Expanded in $1/m_Q$

Operating just once the naive Foldy-Wouthuysen-Tani transformation on the Schrödinger equation for $Q\bar q$ bound states described by a hamiltonian, we systematically develop a perturbation theory in $1/m_Q$ which enables one to solve the Schrödinger equation to obtain masses and wave functions of the bound states in any order of $1/m_Q$. It is shown that positive energy projection with respect to the heavy quark sector of a wave function is, at each order of perturbation, proportional to the 0-th order solution. There appear also negative components of the wave function except for the 0-th order, which contribute also to higher order corrections to masses.

hep-ph↗

arXiv1995

Spectroscopy and Decays of Heavy Mesons

Assuming Coulomb-like as well as confining scalar potential, we have solved Shrödinger equation perturbatively in $1/m_Q$ with a heavy quark mass $m_Q$. The lowest order equation is examined carefully. Mass levels are fitted with experimental data for $D/B$ mesons at each level of perturbation. Meson wave functions obtained thereby can be used to calculate ordinary form factors as well as Isgur-Wise functions for semileptonic weak decays and other physical quantities. All the above calculations are expanded in $1/m_Q$ order by order to determine parameters as well as to compare with results of Heavy Quark Effective Theory.

hep-ph↗