D. Mercier

Search for Heavy Stable Charged Particles in pp collisions at sqrt(s)=7 TeV

The result of a search at the LHC for heavy stable charged particles produced in pp collisions at

First measurement of hadronic event shapes in pp collisions at √s=7 TeV

\sqrt {s} = 7\;{\text{TeV}}

Dijet Azimuthal Decorrelations in pp Collisions at sqrt(s) = 7 TeV

is described. The data sample was collected with the CMS detector and corresponds to an integrated luminosity of 3.1 pb−1. Momentum and ionization-energy-loss measurements in the inner tracker detector are used to identify tracks compatible with heavy slow-moving particles. Additionally, tracks passing muon identification requirements are also analyzed for the same signature. In each case, no candidate passes the selection, with an expected background of less than 0.1 events. A lower limit at the 95% confidence level on the mass of a stable gluino is set at 398GeV/c2, using a conventional model of nuclear interactions that allows charged hadrons containing this particle to reach the muon detectors. A lower limit of 311 GeV/c2 is also set for a stable gluino in a conservative scenario of complete charge suppression, where any hadron containing this particle becomes neutral before reaching the muon detectors.

Bimodal behavior of the heaviest fragment distribution in projectile fragmentation.

Hadronic event shapes have been measured in proton-proton collisions at √ s = 7 TeV, with a data sample collected with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 3.2 pb−1. Event-shape distributions, corrected for detector response, are compared with five models of QCD multijet production. Submitted to Physics Letters B ∗See Appendix A for the list of collaboration members ar X iv :1 10 2. 00 68 v1 [ he pex ] 1 F eb 2 01 1

The prominent role of the heaviest fragment in multifragmentation and phase transition for hot nuclei

Measurements of dijet azimuthal decorrelations in pp collisions at √ s = 7 TeV using the CMS detector at the CERN LHC are presented. The analysis is based on an inclusive dijet event sample corresponding to an integrated luminosity of 2.9 pb−1. The results are compared to predictions from perturbative QCD calculations and various Monte Carlo event generators. The dijet azimuthal distributions are found to be sensitive to initial-state gluon radiation. Submitted to Physical Review Letters ∗See Appendix A for the list of collaboration members ar X iv :1 10 1. 50 29 v2 [ he pex ] 2 1 A pr 2 01 1

Upsilon production cross section in pp collisions at

The charge distribution of the heaviest fragment detected in the decay of quasiprojectiles produced in intermediate energy heavy-ion collisions has been observed to be bimodal. This feature is expected as a generic signal of phase transition in nonextensive systems. In this Letter, we present new analyses of experimental data from Au on Au collisions at 60, 80, and 100 MeV/nucleon showing that bimodality is largely independent of the data selection procedure and of entrance channel effects. An estimate of the latent heat of the transition is extracted.

\sqrt{s}

The role played by the heaviest fragment in partitions of multifragmenting hot nuclei is emphasized. Its size/charge distribution (mean value, fluctuations and shape) gives information on properties of fragmenting nuclei and on the associated phase transition.