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Register a new userPossible existence of a meson ($sbar s$) S = 0 at M $approx$ 762 MeV
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The possible existence of a ($ sbar s$) S = 0 meson at M $approx$ 762 MeV is discussed through a critical analysis of the existing data. Different experimental results are considered and show the possibility that the presence of such meson is not excluded by the data, but may be hidden by more excited mesons at nearby masses.
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The possibility of the $0^+$ $etaeta$ resonance $f_0(2100)$ as a candidate of the $Q^2bar{Q}^2$ state $C^{ss}(36)$ is explored. The $etaeta$ channel of $f_0(2100)$ is the dominant decay mode, $etaeta$ channel has less decay rate, the decay rate of the $etaeta$ channel is very small. The $pipi,;Kbar{K},;4pi$ modes are at next leading order in $N_C$ expansion. Other possible decay modes are discussed.
We report the first search for the penguin-dominated process $B_{s}^{0} rightarrow eta^{prime} X_{sbar{s}}$ using a semi-inclusive method. A 121.4 $mathrm{fb}^{-1}$ integrated luminosity $Upsilon(5S)$ data set collected by the Belle experiment, at the KEKB asymmetric-energy $e^+e^-$ collider, is used. We observe no statistically significant signal and including all uncertainties, we set a 90% confidence level upper limit on the partial branching fraction at 1.4 $times$ 10$^{-3}$ for $M(X_{sbar{s}})$ $leq$ 2.4 GeV/$c^{2}$.
Production of prompt D$^0$ mesons is studied in proton-lead and lead-proton collisions recorded at the LHCb detector at the LHC. The data sample corresponds to an integrated luminosity of $1.58pm0.02$ nb$^{-1}$ recorded at a nucleon-nucleon centre-of-mass energy of $sqrt{s}=5$ TeV. Measurements of the differential cross-section, the forward-backward production ratio and the nuclear modification factor are reported using D$^0$ candidates with transverse momenta less than 10 GeV/c and rapidities in the ranges $1.5<y^*<4.0$ and $-5.0<y^*<-2.5$ in the nucleon-nucleon centre-of-mass system.
he $B(E2,2^+ rightarrow 0^+)$ transition strengths of the T=1 isobaric triplet $^{70}$Kr, $^{70}$Br, $^{70}$Se, recently measured at RIKEN/RIBF, are discussed in terms of state of the art large scale shell model calculations using the JUN45 and JUN45+LNPS plus Coulomb interactions. In this letter we argue that, depending on the effective charges used, the calculations are either in line with the experimental data within statistical uncertainties, or the anomaly happens in $^{70}$Br, rather than $^{70}$Kr. In the latter case, we suggest that it can be due to the presence of a hitherto undetected 1$^+$ T=0 state below the yrast 2$^+$ T=1 state. Our results do not support a shape change of $^{70}$Kr with respect to the other members of the isobaric multiplet.
Photon strength, $f(E_{gamma})$, measured in photonuclear reactions, is the product of the average level density per MeV, $rho(E_x)$, and the average reduced level width, $Gamma_{gamma}/E_{gamma}^3$ for levels populated primarily by E1 transitions at an excitation energy $E_x=E_{gamma}$. It can be calculated with the Brink-Axel (BA) formulation modified to include contributions from the Giant Dipole Resonance (GDR) and higher lying resonances. Level densities and reduced widths have been calculated for 17 nuclei with atomic numbers between Z=14-92. Level densities below the GDR energy were calculated with the CT-JPI model and combined with the BA photon strength to determine the associated reduced widths. The reduced widths varied exponentially with level energy and could be extrapolated up to higher energies. The extrapolated widths were then combined with the BA photon strength to determine the level densities at higher energies. The level densities are found to increase exponentially at low energies, peak near the GDR energy due to the appearance of new states at the $2hbaromega$ shell closure, and continue to increase less rapidly up to at least 30 MeV. The average level densities have been compared with the Fermi Gas Level Density (FGLD), Back-Shifted Fermi Gas (BSFG), and Hartree-Fock-Bogoliubov (HFB) models. Good agreement is found with the nearly identical FGLD and BDFG models, while the HFB models gives substantially lower level densities. A universal set of FGLD model parameters were determined as a function of mass and temperature that are applicable to all nuclei.
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