Effective mass and decay of ${\Theta }^{+}$ in nuclear matter in quark-meson coupling model

Abstract

The in-medium mass of a $\thetaplus$, $\mtheta^*$, in cold symmetric nuclear matter is calculated by using the quark-meson coupling model. The ${\Theta }^{+}$ is treated as an MIT bag with the quark content $uudd\bar{s}$. Bag parameters for a free $\thetaplus$ are fixed to reproduce the observed mass of the $\thetaplus$. In doing so, we use three different values of the $s$-quark mass since the mass of the $s$-quark is not well known. As usual, the strengths of the $u$ and $d$ quark couplings to $\sigma$- and $\omega$-meson fields are determined to fit the nuclear saturation properties. However, the coupling constant $g_{\sigma }^s$ between the $s$-quark and the $\sigma$-meson cannot be fixed from the saturation properties, and thus we treat $g_{\sigma }^s$ as a free parameter and investigate how $\mtheta^*$ depends on $g_{\sigma }^s$. %$\mtheta^*$ is calculated up to 2.5 times the nuclear saturation density, %and we find that We find that $\mtheta^*$ depends significantly on the value of $g_{\sigma }^s$ but not on the mass of the $s$-quark. Chemical potentials of the ${\Theta }^{+}$ and the $K+N$ system are calculated to discuss the decay of a ${\Theta }^{+}$ in nuclear matter. We calculate the effective mass of a kaon in nuclear matter in two ways; using the optical potential of $K^{-}$ in matter and using quark model. By comparing the effective masses calculated from these two methods, we find the magnitude of the real part of the optical potential that is consistent with the usual quark model is about 100 MeV.

arXiv comment16 pages, 4 figures, 3 tables

References in corpus (24)

• Evidence for Narrow S=+1 Baryon Resonance in Photo-production from Neutron
• Exotic Anti-Decuplet of Baryons: Prediction from Chiral Solitons
• Observation of an Exotic $S=+1$ Baryon in Exclusive Photoproduction from the Deuteron
• Observation of a baryon resonance with positive strangeness in K+ collisions with Xe nuclei
• Evidence for the positive-strangeness pentaquark ${\Theta }^{+}$ in photoproduction with the SAPHIR detector at ELSA
• The properties of \bar{K} in the nuclear medium
• A quark-meson model for nuclear and neutron matter
• Low-mass e+e- pair production in 158 A GeV Pb-Au collisions at the CERN SPS, its dependence on multiplicity and transverse momentum
• First Order Kaon Condensate
• First observation of in-medium modifications of the omega meson
• In-medium Production of Kaons at the Mean-Field Level
• Kaonic nuclei studied based on a new framework of Antisymmetric Molecular Dynamics
• Neutron star properties in the quark-meson coupling model
• In-medium kaon and antikaon properties in the quark-meson coupling model
• Observation of $\rho /\omega$ Meson Modification in Nuclear Matter
• Modified Quark-Meson Coupling Model for Nuclear Matter
• Recovering Relativistic Nuclear Phenomenology from the Quark-Meson Coupling Model
• Pentaquark baryon production at the Relativistic Heavy Ion Collider
• A search for deeply bound kaonic nuclear states
• Production of the exotic Theta baryon in relativistic nuclear collisions
• Study of $\Lambda$ hypernuclei in the quark mean field model
• Strange Pentaquark Hadrons in Statistical Hadronization
• An Experimental Review of the ${\Theta }^{+}$ Pentaquark
• Pentaquark ${\Theta }^{+}$ in nuclear matter and ${\Theta }^{+}$ hypernuclei

Cited by in corpus (1)

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