123957691
Study on a Cellmap for the Reconstruction of Cosmic Ray Tracks in Drift Chamber
Taking L3 Cosmics experiment (L3 + C) as an example, we discussed a new Cellmap to reconstruct the hit in drift chamber of magnetic spectrometer for the very inclined comic-ray tracks, and compared the reconstruction results with the standard Cellmap of L3 + C. It shows that, for the very inclined cosmic-ray tracks, the new Cellmap can reconstruct more hits than the standard Cellmap, and the distribution of chi(2) of track reconstruction is also improved.
115136998
Search for a Muon Flux Enhancement During the Solar Flare of 14 July 2000 with the L3+C Data
The solar slare of the 14 July 2000 offers a unique opportunity for the L3+C experiment at CERN to search for a correlated enhancement in the flux of muons using the precision spectrometer. The search for a directional excess in the flux of muons between 15 and 25 GeV, corresponding to primary proton energies above 40 GeV, is presented. We report an excess with a chance probability of 2.7 · 10−3 at a time coincident with the peak increase of solar protons observed with neutron monitors and satellites. At higher energies no significant signal has been observed up to 1.5 hours after the Solar flare time.
117951678
Searching for Point Source Signals through Muons
121855913
Possibility to Detect Upgoing Sleptons
Some supersymmetric models predict long lived charged sleptons. If they are exist, the τ ˜ , the supersymmetry partner of τ lepton, could be produced inside the earth by collisions of high energy neutrinos with nucleons. The possible signals of upgoing τ ˜ have been studied in various ways. Taking the atmospheric neutrino flux into account, the muon flux as main background is also estimated. By using the Waxman-Bahcall limit on the extraterrestrial neutrino flux, the resultant spectra show that there are about 70 events per year passing a km-scale underground experiment, such as ICECUBE.
118365916
Geminga Pulsar in Cos-B and Heao-B Observations
117504817
The X-ray spectra and XUV excess of some AGNs.
119236022
Estimates for X ( 4350 ) decays from the effective Lagrangian approach
The strong and electromagnetic decays of X(4350) with quantum numbers J{sup P}=0{sup ++} and 2{sup ++} have been studied by using the effective Lagrangian approach. The coupling constant between X(4350) and D{sub s}*D{sub s0}* is determined with the help of the compositeness condition which means that X(4350) is a bound state of D{sub s}*D{sub s0}*. Other coupling constants applied in the calculation are determined phenomenologically. Our numerical results show that, using the present data, the possibility that X(4350) is a D{sub s}*D{sub s0}* molecule cannot be ruled out within the present model.
119280184
$D$ and $D^{\ast}$ meson mixing in spin-isospin correlated cold nuclear matter
We propose to study the mass spectrum of the heavy-light mesons to probe the structure of the spin-isospin correlation in the nuclear medium. We point out that the spin-isospin correlation in the nuclear medium generates a mixing among the heavy-light mesons carrying different spins and isospins such as $D^+$, $D^0$, $D^{\ast +}$, and $D^{\ast 0}$ mesons. We use two types of correlations motivated by the skyrmion crystal and the chiral density wave as typical examples to obtain the mass splitting caused by the mixing. Our result shows that the structure of the mixing reflects the pattern of the correlation, i.e., the remaining symmetry. Furthermore, the magnitude of the mass modification provides information of the strength of the correlation.
59430684
Chiral partner structure of heavy baryons from the bound state approach with hidden local symmetry
The chiral partner structure of heavy baryons is studied using the bound state approach by binding the heavy-light mesons to the nucleon as the soliton in an effective Lagrangian for the pseudoscalar and vector mesons based on hidden local symmetry. In the heavy-light meson sector, we regard the $H$ doublet and $G$ doublet as chiral partners and couple them to light mesons with a minimal derivative. We find that the chiral partner of ${\ensuremath{\Lambda}}_{c}(\frac{1}{2}\genfrac{}{}{0}{}{{}^{+}}{},2286)$ is the ${\ensuremath{\Lambda}}_{c}(\frac{1}{2}\genfrac{}{}{0}{}{{}^{\ensuremath{-}}}{},\frac{3}{2}\genfrac{}{}{0}{}{{}^{\ensuremath{-}}}{})$ heavy quark doublet with a mass of about 3.1 GeV but not (${\ensuremath{\Lambda}}_{c}(\frac{1}{2}\genfrac{}{}{0}{}{{}^{\ensuremath{-}}}{},2595)$, ${\ensuremath{\Lambda}}_{c}(\frac{3}{2}\genfrac{}{}{0}{}{{}^{\ensuremath{-}}}{},2625)$), which might be interpreted as an orbital excitation of ${\ensuremath{\Lambda}}_{c}(\frac{1}{2}\genfrac{}{}{0}{}{{}^{+}}{},2286)$. The same model is applied to the bottom sector, and the chiral partner of ${\ensuremath{\Lambda}}_{b}(\frac{1}{2}\genfrac{}{}{0}{}{{}^{+}}{},5625)$ is shown to have a mass of about 6.5 GeV. We also discuss the chiral partner structures for the isospin vector heavy baryons. For the pentaquark states, we find that the masses of the pentaquark state made of a ground state heavy-light meson and its chiral partner are similar, and both of them are below the $Dp$ threshold, which therefore cannot be ruled out by the present data.
118442618
Strong and electromagnetic decays of X(1835) as a baryonium state
With the assumption that the recently observed X(1835) is a baryonium state we have studied the strong decays of X(1835) → η(')π+π−, η(')π0π0 and the electromagnetic decay of X(1835) → 2γ in the framework of effective Lagrangian formalism. In the present investigation, we have included the contributions from the iso-singlet light scalar resonances but we have not included the isospin violating effect. Our result for the strong decay of X(1835) → η'π+π− is smaller than the observed data. The decay width for the radiative decay of X(1835) → 2γ is consistent with the assumption that it decays through the glueball. In addition, the width for the strong decay of X(1835) → ηπ+π− is larger than that for the strong decay of X(1835) → η'π+π− due to the large phase space and coupling constant . From our investigation, it is not possible to interpret X(1835) as a baryonium.
118615785
Dense baryonic matter in conformally-compensated hidden local symmetry: Vector manifestation and chiral symmetry restoration
We find that, when the dilaton is implemented as a (pseudo-)Nambu-Goldstone boson using a conformal compensator or "conformon" in a hidden gauge symmetric Lagrangian written to $O(p^4)$ from which baryons arise as solitons, namely, skyrmions, the vector manifestation and chiral symmetry restoration at high density predicted in hidden local symmetry theory --- which is consistent with Brown-Rho scaling --- are lost or sent to infinite density. It is shown that they can be restored if in medium the behavior of the $\omega$ field is taken to deviate from that of the $\rho$ meson in such a way that the flavor $U(2)$ symmetry is strongly broken at increasing density. The hitherto unexposed crucial role of the $\omega$ meson in the structure of elementary baryon and multibaryon systems is uncovered in this work. In the state of half-skyrmions to which the skyrmions transform at a density $n_{1/2}^{} \gtrsim n_0^{}$ (where $n_0^{}$ is the normal nuclear matter density), characterized by the vanishing (space averaged) quark condensate but nonzero pion decay constant, the nucleon mass remains more or less constant at a value $\gtrsim$ 60 \% of the vacuum value indicating a large component of the nucleon mass that is not associated with the spontaneous breaking of chiral symmetry. We discuss its connection to the chiral-invariant mass $m_0^{}$ that figures in the parity-doublet baryon model.