No Arabic abstract
Inspired by the event accumulation around 2.6 GeV in the $eta^primepi^+pi^-$ invariant mass spectrum of $J/psito gamma eta^primepi^+pi^-$, which was reported by the BESIII Collaboration, we carry out the study of the mass spectrum and decay behavior of four radial excitations in the pseudoscalar meson family, which include $eta^{(prime)}(6S)$ and $eta^{(prime)}(7S)$. Combining with these analysis, we present the calculation of the reactions induced by a pion or kaon on the proton target which are relevant to these four discussed states. According to this information, we give concrete experimental suggestion of searching for them, which will become a new task for future experiments.
A symmetry-preserving regularisation of a vector$times$vector contact interaction (SCI) is used to deliver a unified treatment of semileptonic transitions involving $pi$, $K$, $D_{(s)}$, $B_{(s,c)}$ initial states. The framework is characterised by algebraic simplicity, few parameters, and the ability to simultaneously treat systems from Nambu-Goldstone modes to heavy+heavy mesons. Although the SCI form factors are typically somewhat stiff, the results are comparable with experiment and rigorous theory results. Hence, predictions for the five unmeasured $B_{s,c}$ branching fractions should be a reasonable guide. The analysis provides insights into the effects of Higgs boson couplings via current-quark masses on the transition form factors; and results on $B_{(s)}to D_{(s)}$ transitions yield a prediction for the Isgur-Wise function in fair agreement with contemporary data.
We study, at leading order in the large number of colours expansion and within the Resonance Chiral Theory framework, the odd-intrinsic-parity $e^+ e^- rightarrow pi^+ pi^- (pi^0, eta)$ cross-sections in the energy regime populated by hadron resonances, namely $3 , m_{pi} lsim E lsim 2 , mbox{GeV}$. In addition we implement our results in the Monte Carlo generator PHOKHARA 7.0 and we simulate hadron production through the radiative return method.
We explore the detection possibility of light pseudoscalar Higgs boson in the next-to-minimal supersymmetric Standard Model(NMSSM) at the LHC with the center of mass energy, $sqrt{S}=13$ TeV. We focus on the parameter space which provides one of the Higgs boson as the SM-like with a mass of 125 GeV and some of the non-SM-like Higgs bosons can be light having suppressed couplings with fermions and gauge bosons due to their singlet nature. It is observed that for certain region of model parameter space, the singlet like light pseudoscalar can decay to di-photon($gammagamma$) channel with a substantial branching ratio. In this study, we consider this di-photon signal of light pseudoscalar Higgs boson producing it through the chargino-neutralino production and the subsequent decay of neutralino. We consider signal consisting of two photons plus missing energy along with a lepton from the chargino decay. Performing a detailed simulation of the signal and backgrounds including detector effects, we present results for a few benchmark points corresponding to the pseudoscalar Higgs boson mass in the range 60 -100 GeV. Our studies indicate that some of the benchmark points in the parameter space can be probed with a reasonable significance for 100 fb$^{-1}$ integrated luminosity. We also conclude that exploiting this channel it is possible to distinguish the NMSSM from the other supersymmetric models.
We discuss the current status of our calculation of the physics of pi and K mesons using three dynamical flavors of improved staggered quarks. This year, we have a new ensemble with a lattice spacing of 0.06 fm and a light sea mass of 0.2 m_s, as well as significant increases in statistics at several coarser lattice spacings and/or heavier sea masses. Results for decay constants, quark masses, low energy constants, condensates, and V_{us} are presented.
We study the twist-2 distribution amplitudes (DAs) and the decay constants of pseudoscalar light ($pi$, $K$) and heavy ($D$, $D_s$, $B$, $B_s$) mesons as well as the longitudinally and transversely polarized vector light ($rho$, $K^*$) and heavy ($D^*$, $D_s^*$, $B^*$, $B_s^*$) mesons in the light-front quark model with the Coulomb plus exponential-type confining potential $V_{rm {exp}} = a + b e^{alpha r}$ in addition to the hyperfine interaction. We first compute the mass spectra of ground state pseudoscalar and vector light and heavy mesons and fix the model parameters necessary for the analysis, applying the variational principle with the trial wave function up to the first three lowest order harmonic oscillator (HO) wave functions $Phi(x, textbf{k}_bot) = sum_{n=1}^{3} c_n phi_{nS}$. We then obtain the numerical results for the corresponding decay constants of light and heavy mesons. We estimate the DAs, analyze their variation as a function of momentum fraction and compute the first six $xi$-moments of the $B$ and $D$ mesons as well. We compare our results with the available experimental data as well as with the other theoretical model predictions.