120493940
HEAVY STABLE CHARGED PARTICLE SEARCHES AT THE LHC
Several searches for heavy stable charged particles have recently been performed using data from $\sqrt{s} = 7 {\rm TeV}$pp collisions at the Large Hadron Collider (LHC). This review summarizes some of the theoretical and experimental motivations for such searches, and discusses searches for stable squarks, stable gluino, stable sleptons and multiply charged heavy stable particles with the CMS and ATLAS detectors.
119107849
Bose symmetry interference effects of 4 pi final states
We analyze the relative branching ratios of 4 pi final states pi(+)pi(-)pi(+)pi(-), pi(+)pi(-)pi(0)pi(0), and pi(0)pi(0)pi(0)pi(0), from various resonances with J(PC) = 0(++), 0(-+), 2(++). We find that in some cases the interference effects due to Bose symmetry make their ratios obviously different from the naive counting values without these effects. The results allow an accurate estimate of the 4 pi branching ratios of relevant resonances when only one (or two) modes are measured in a given experiment.
119179797
Searching for high speed long-lived charged massive particles at the LHC
The conventional way to search for long-lived CHArged Massive Particles (CHAMPs) is to identify slow (small β) tracks using delayed time of flight and high ionization energy loss. But at the 7–14 TeV center of mass energy of the LHC, a CHAMP may be highly boosted (high β) and therefore look more like a minimum ionizing particle, while for high momentum muons (≳500 GeV/c) the radiative effect dominates energy deposition. This suggests a new strategy to search for CHAMPs at the LHC. Using energy deposition from different detector components, we construct a boosted decision tree discriminant to separate high momentum CHAMPs from high momentum muons. This method increases substantially the CHAMP discovery potential and it can be used to distinguish possible di-CHAMP or CHAMP–muon resonance models from di-muon resonance models. We illustrate the new method using a mGMSB model and a recently proposed di-CHAMP model and we give updated CHAMP mass limits for these two models using the results from a recent CDF CHAMP search.
18805981
System size and energy dependence of phi meson production at RHIC
We present a system size and energy dependence of meson production in Cu + Cu and Au + Au collisions at GeV and 200 GeV measured by the STAR experiment at RHIC. We find that the number of participant scaled meson yields in heavy-ion collisions over that of p + p collisions are larger than 1 and increase with collision energy. We compare the results with those of open-strange particles and discuss the physics implication.
118981397
125 GeV Higgs boson decays in the μ from ν supersymmetric standard model
Recently the ATLAS and CMS Collaborations have reported significant events that are attributed to the neutral Higgs boson with mass around 125 GeV. In this work, we investigate the signals of the Higgs boson decay channels $h\rightarrow\gamma\gamma$, $h\rightarrow VV^*$ ($V=Z,W$), and $h\rightarrow f\bar{f}$ ($f=b,\tau$) in the $\mu$ from $\nu$ supersymmetric standard model ($\mu\nu$SSM). In the numerical results, we show the light stop and stau effects on the signal strengths for the 125 GeV Higgs boson decay channels in the $\mu\nu$SSM, which can account for the updated experimental data on Higgs.
123049469
Directed flow measurements from STAR
STAR measurements of v1 for identified particles for Au+Au collisions at = 200 GeV are presented. A negative v1 slope is observed for pions, protons, antiprotons and kaons (K0S) in 10-70% central collisions. For pion v1 slope, the comparison between the current result and available models (RQMD, UrQMD, AMPT, QGSM and hydro model with a tilted source) is made. In 5-30% central collisions, surprisingly sizable difference between v1 of protons and antiprotons is observed. The centrality and energy dependence of proton v1 are also presented. The charged hadron v1 for Cu+Cu collisions at = 22.4 GeV is measured and compared with results obtained previously.
122340199
Multijet and single diffraction dissociation Monte Carlo generator
We have built a Monte Carlo generator for simulating propagation of cosmic ray particles in the atmosphere. The core of the generator is ap-air nuclear interaction model in which SD and NSD processes are included in the inelastic collisions. Based on QCD partonic theory, multiple minijet production is described in detail in the NSD process. A phase-space model is used for the SD process in our work. This generator reproduces cosmic ray experimental data well at very high energies.
124840820
Finite-temperature nuclear matter properties within a relativistic σ − ω coupling model
We use the relativistic mean field theory to study the finite temperature nuclear matter properties. The effects of isoscalar $\ensuremath{\sigma}\text{\ensuremath{-}}\ensuremath{\omega}$ coupling on the equation of state and finite temperature properties of symmetric and asymmetric nuclear matter are investigated carefully. For comparison, we also discuss the properties of two nonlinear $\ensuremath{\sigma}$ self-coupling models, namely NL-SH and NL3. It is found that the $\ensuremath{\sigma}\text{\ensuremath{-}}\ensuremath{\omega}$ coupling term can soften the equation of state, but has very limited influence to the critical temperature of the nuclear matter liquid-gas phase transition.