Alain Givernaud

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

Particle Multiplicities in K- p Interactions at 32-GeV/c

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

First measurement of hadronic event shapes in pp collisions at √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.

Vector and tensor meson production in K−p interactions at 32 GeV/c

The inclusive cross section and the average multiplicity are evaluated for most of the charged (π±, p, K±) and neutral (γ, π0, K0, K0, Λ, Λ, n) particles produced in 32 GeV/c K−p interactions; corresponding results are obtained for each charged topology separately. New results are given for the total charged multiplicity cross sections. The average longitudinal momentum of neutrals is found to be roughly equal to that of charged particles. The π+ and π− multiplicity distributions are reconstructed and compared to the π0 and to the total charged multiplicity distributions.

Inclusive production of charged pions in K−p interactions at 32 GeV/c

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

Results from tests on matrices of lead tungstate crystals using high energy beams

Inclusive production of vector and tensor mesons is studied in a K−p experiment at 32 GeV/c in the MIRABELLE bubble chamber. The K∗0(890), ϱ0 and ω cross sections are comparable, about 4 mb each. The K∗0(1420 and cross sections are also comparable, about 1 mb each. The K∗o+(890), Φ, K∗o−(1420) and f cross sections beam fragmentation; ϱ production is almost forward-backward symmetric in the c.m.s. The pT production slopes of K∗o−(890) and ϱ are similar, the Φ slope is shallower. Vector and tensor mesons alone are responsible for ≅50% (≅60%) of final-state pions

Single and double diffractive dissociation in K−p interactions at 32 GeV/c

Abstract Results are presented on the inclusive π ± production in K − p interactions at 32.1 GeV/ c . The invariant longitudinal distributions have been calculated both for π + and π − in the backward c.m. hemisphere and extrapolated in the forward hemisphere under some physical assumptions. The inclusive cross sections for π + and π − amount to 32.9 ± 1.5 mb and 35.0 ± 0.7 mb respectively. The energy dependence of the inclusive pion production has been analyzed in the framework of Mueller-Regge phenomenology both in the proton fragmentation and in the central region.

Non-diffractive two-body channels in reactions K+p→K0π+p and K+p→K+π−π+p at 32 Gev/c

The performance of lead tungstate crystals using photomultipliers and Si avalanche photodiodes to detect the scintillation light has been studied using high energy electron, pion and muon beams at CERN. Results from tests carried out in 1993 and 1994 are presented. Good energy resolution has been obtained using photomultipliers. Some further development is required of crystals and avalanche photodiodes in order to achieve a performance, with avalanche photodiode readout, similar to that obtained using photomultipliers.

Systematics of exclusive diffraction dissociation modes inK± p interactions at 32 GeV/c

Data from a high statistics Mirabelle bubble chamber K−p experiment at 32 GeV/c are used to study inclusive single and double diffraction dissociation. From the reaction K−p → K− + X we find a total proton single dissociation cross section of 1040 ± 120 μb, with comparable contributions from proton dissociations into 1 and 3 charged particles. There is evidence for double dissociation in K−p → (K−π+π−) + X+, with cross section of 64 ± 20 μb. Cross sections and dσdt′ distributions are in qualitative agreement with the factorization hypothesis. With the results from a companion K+p experiment, the total diffractive cross section (elastic + SD + DD) is estimated. It amounts to ≅4.75 mb, i.e., about 25% of the total KN cross section and about 50% of Pumplins upper bound for the diffractive cross section. A comparison with ISR data suggests that the total DD cross section increases by ∼2 mb over the c.m. energy range from ∼10 to ∼50 GeV.

Diffractive dissociation in exclusive K−p reactions at 32 GeV/c and comparison with results at 10, 14.3 and 16 GeV/c

Abstract We present results on a number of non-diffractive two-body channels contributing to reactions K+p→K0π+p and K+p→K+π−π+p. The data come from an exposure of the Mirabelle bubble chamber to an r.f. separated K+ beam of 32 GeV/c at the Serpukhov accelerator. Total cross sections are given for the final states K ∗+ (890) p , K ∗+ (1420) p , K 0 Δ ++ (1232), K ∗+ (890) p , Δ ++ (1232), K ∗0 (1420) Δ ++ (1232), K ∗0 (1780) Δ ++ (1232) and K ∗0 (890) Δ ++ (1950) . The differential cross sections are given for all channels with sufficient statistics. The energy dependence of the total and differential cross sections is studied.