Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userNonrelativistic Quark Model Calculation of the S parameter
65
0
0.0
(
0
)
Authors
Carlos A. Ramirez
Ask ChatGPT about the research
No Arabic abstract
A critical review is presented of the attempts to estimate the Strong Interactions contributions to the parameter $S$ ($L_{10}$ in the QCD Chiral Version). In particular it is discussed why the estimations done for Technicolor are unreliable. $S$ is calculated for heavy doublets of Techniquarks using the Nonrelativistic Quark Model and keeping $vsimeq 0.25$ TeV fixed. It is found that heavy Techniquarks decouple, so it is possible to obtain values for $S$ in agreement with present experimental data.
rate research
Read More
Using the newly measured masses of $B_c(1S)$ and $B_c(2S)$ from the CMS Collaboration and the $1S$ hyperfine splitting determined from the lattice QCD as constrains, we calculate the $B_c$ mass spectrum up to the $6S$ multiplet with a nonrelativistic linear potential model. Furthermore, using the wave functions from this model we calculate the radiative transitions between the $B_c$ states within a constituent quark model. For the higher mass $B_c$ states lying above $DB$ threshold, we also evaluate the Okubo-Zweig-Iizuka (OZI) allowed two-body strong decays with the $^{3}P_{0}$ model. Our study indicates that besides there are large potentials for the observations of the low-lying $B_c$ states below the $DB$ threshold via their radiative transitions, some higher mass $B_c$ states, such as $B_c(2^3P_2)$, $B_c(2^3D_1)$, $B_c(3^3D_1)$, $B_c(4^3P_0)$, and the $1F$-wave $B_c$ states, might be first observed in their dominant strong decay channels $DB$, $DB^*$ or $D^*B$ at the LHC for their relatively narrow widths.
The narrow peak recently found in various pionic double charge exchange (DCX) cross sections can be explained by the assumption of a universal resonance at 2065 MeV, called d. We calculate the mass of a six-quark system with J^P=0^-, T=0 quantum numbers employing a cluster model and a shell model basis to diagonalize the nonrelativistic quark model Hamiltonian.
The kaon B parameter is calculated in quenched lattice QCD with the Wilson quark action. The mixing problem of the Delta s=2 four-quark operators is solved non-perturbatively with full use of chiral Ward identities, and this method enables us to construct the weak four-quark operators exhibiting good chiral behavior. We find B_K(NDR, 2GeV)=0.562(64) in the continuum limit, which agrees with the value obtained with the Kogut-Susskind quark action.
We study the $f^+$ form factor for the $bar B_sto K^+ell^-bar u_ell$ semileptonic decay in a nonrelativistic quark model. The valence quark contribution is supplemented with a $bar B^*$-pole term that dominates the high $q^2$ region. To extend the quark model predictions from its region of applicability near $q^2_{rm max}=(M_{B_s}-M_K)^2$, we use a multiply-subtracted Omn`es dispersion relation. We fit the subtraction constants to a combined input from previous light cone sum rule results in the low $q^2$ region and the quark model results (valence plus $bar B^*$-pole) in the high $q^2$ region. From this analysis, we obtain $Gamma(bar B_sto K^+ell^-bar u_ell)=(5.47^{+0.54}_{-0.46})|V_{ub}|^2times 10^{-9},{rm MeV}$, which is about 10% and 20% higher than predictions based on Lattice QCD and QCD light cone sum rules respectively.
In this article, the mass spectra of mesons with one or two heavy quarks and their diquarks partners are estimated within a non-relativistic framework by solving Schrodinger equation with an effective potential inspired by a symmetry preserving Poincare covariant vector-vector contact interaction model of quantum chromodynamics. Matrix Numerov method is implemented for this purpose. In our survey of mesons with heavy quarks, we fix the model parameter to the masses of ground-states and then extend our calculations for radial excitations and diquarks. The potential model used in this work gives results which are in good agreement with experimental data and other theoretical calculations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
