TOTEM: The experiment to measure the total proton-proton cross section at LHC

The current large uncertainty on the extrapolation of the proton-proton total cross section at the LHC energy will be resolved by the precise measurement by the TOTEM experiment. Its accurate studies on the basic properties of proton-proton collisions at the maximum accelerator energy could provide a significant contribution to the understanding of cosmic ray physics.Comment: 6 pages, 7 figures, Proceedings XIV International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2006), Weihai, China, August 15-22, 200

La structuration de la desserte militaire sur le réseau PLM (1862-1936)

L’utilisation des chemins de fer par les autorités militaires est connue en ce qui concerne les périodes de conflits et les transports de troupes. Mais la dimension « industrielle » des rapports entre le chemin de fer et l’administration de la Guerre aux xixe et xxe siècles a été peu étudiée. Le cas des embranchements particuliers militaires sur le réseau PLM permet de considérer cette dimension sous un angle différent. Destinés à mettre les établissements commerciaux et industriels en relati..

γγ\gamma \gamma cross-sections and γγ\gamma \gamma colliders

We summarize the predictions of different models for total $\gamma \gamma$ cross-sections. The experimentaly observed rise of $\sigma_{\gamma \gamma}$ with $\sqrt{s_{\gamma \gamma}}$, faster than that for $\sigma_{\bar p p}$, $\sigma_{\gamma p}$ is in agreement with the predictions of the Eikonalized Minijet Models as opposed to those of the Regge-Pomeron models. We then show that a measurement of $\sigma_{\gamma \gamma}$ with an accuracy of $\lessapprox 8-9$ is necessary to distinguish among different Regge-Pomeron type models (among the different parametrisations of the EMM models) and a precision of $\lessapprox$ 20% is required to distinguish among the predictions of the EMMs and of those models which treat like 'photon like a proton', for the energy range $300 < \sqrt{s_{\gamma \gamma}} < 500$ GeV. We further show that the difference in model predictions for $\sigma_{\gamma \gamma}$ of about a factor 2 at $\sqrt{s_{\gamma \gamma}} = 700$ GeV reduces to $\sim$ 30% when folded with bremsstrahlung $\gamma$ spectra to calculate $\sigma ({e^+e^- \to e^+e^-\gamma \gamma \to e^+e^-X})$. We point out then the special role that $\gamma \gamma$ colliders can play in shedding light on thisComment: 11 pages, 8 figures, LaTeX, uses elsart.cls. Talk to appear in the proceedings of the the International Workshop on High Energy Photon Colliders, DESY, Hamburg, June 200

Riconoscimento di studenti trans nel sistema educativo italiano: criticità e prassi per una buona scuola

La letteratura scientifica focalizzata sull’esperienza di studenti trans nelle scuole mette in evidenza come gli istituti scolastici siano un posto ostile per le persone trans, soggette a ripetute forme di aggressione fisica e verbale, bullismo e molestie a sfondo transfobico da parte del gruppo dei pari, il personale docente e non docente. Con lo scopo di contrastare queste problematiche, e riconoscere l’identità e i bisogni delle persone trans, nelle scuole è stata introdotta la carriera alias, il quale permette di delineare delle buone pratiche per salvaguardare il benessere dellз studenti transgender e migliorare la loro esperienza scolastica. Dai regolamenti degli istituti che hanno introdotto la carriera alias emerge come, in Italia, l’esperienza trans sia ancora fortemente patologizzata tanto che, per la sua attivazione, è spesso richiesta una documentazione medico-psicologica. Inoltre, numerose buone prassi, quali l'accesso a servizi igienici e spogliatoi basati sul loro genere, o formazioni per il personale scolastico e il corpo studentesco, risultano assenti o implementate incorrettamente. Con questo articolo lз autorз, tenendo conto delle particolarità del sistema educativo italiano, propongono delle buone prassi che possano contribuire a migliorare lo strumento della carriera alias, integrandolo con nuove proposte che permettano allз studenti trans maggior riconoscimento e tutela durante il percorso scolastico. Ulteriore obiettivo è quello di dare al personale scolastico indicazioni utili sia per rispondere ai bisogni dellз alunnз trans, sia per portare all’interno del contesto scolastico un cambiamento che metta in discussione i valori cisnormativi.Scientific literature focusing on the experience of trans students highlights how schools are hostile places for trans people. Indeed, they are subjected to repeated forms of physical and verbal aggression, bullying, and transphobic harassment by the peer group, teaching, and non-teaching staff. To counter these issues and recognise the identity and needs of trans people, schools have introduced the alias career (carriera alias). The device outlines good practices to protect the well-being of transgender students and improve their school experience. The regulations of the institutes that have introduced the alias career show that in Italy, the trans experience is still strongly pathologised to the extent that medical-psychological documentation is often required for its activation. Moreover, many good practices, such as access to toilets and changing rooms, or training for school staff and student body, are absent or implemented incorrectly. With this article, the authors, by taking into account the Italian education system's peculiarities, propose good practices that can help improve the alias career by supplementing it with new proposals that allow students to be recognised and protected during their years of schooling. A further aim is to provide guidance to the school staff in responding to the needs of trans pupils and bringing change within the school context by restructuring cisnormative value systems

Can perturbative QCD predict a substantial part of diffractive LHC/SSC physics?

We examine a model of hadronic diffractive scattering which interpolates between perturbative QCD and non-perturbative fits. We restrict the perturbative QCD resummation to the large transverse momentum region, and use a simple Regge-pole parametrization in the infrared region. This picture allows us to account for existing data, and to estimate the size of the perturbative contribution to future diffractive measurements. At LHC and SSC energies, we find that a cut-off BFKL equation can lead to a measurable perturbative component in traditionally soft processes. In particular, we show that the total pp cross section could become as large as 228 mb (160 mb) and the rho parameter as large as 0.23 (0.24) at the SSC (LHC).Comment: 9 pages, McGill/92-3

A Strategy for the Analysis of Semi-Inclusive Deep Inelastic Scattering

We present a strategy for the systematic extraction of a vast amount of detailed information on polarized parton densities and fragmentation functions from semi-inclusive deep inelastic scattering l+N -> l+h+X, in both LO and NLO QCD. A method is suggested for estimating the errors involved in the much simpler, and therefore much more attractive, LO analysis. The approach is based upon a novel interplay with data from inclusive DIS and from e+e- -> hX, and leads to a much simplified form of the NLO expressions. No assumptions are made about the equality of any parton densities and the only symmetries utilised are charge conjugation invariance and isotopic spin invariance of strong interactions.Comment: 26 pages, one section (Sect.2) is removed, Sects.1,2,3,4 are changed, the main content of the paper is not changed, to appear in Nucl. Phys.

Behaviour of the forward peak in hard diffractive leptoproduction of vector mesons

The measured forward slope in elastic and inelastic leptoproduction of vector mesons differ by a substantial amount. In an attempt to describe this phenomenon we construct a two radii model for the target proton, and estimate the effective parameters of the hard Pomeron obtained from a pQCD dipole model with eikonal shadowing corrections (SC). We show that the SC reduce the intercept of the hard Pomeron and generate an effective shrinkage of the forward peak and a diffractive dip at $|t| \approx 1 GeV^2$, which appears to affect the value of the experimentally measured slope.Comment: 18 pages, 7 figures, one table, everything in tar.gz fil

QCD and hybrid NBD on oscillating moments of multiplicity distributions in lepton- and hadron-initiated reactions

QCD predictions for moments of multiplicity distributions are compared with experimental data on e+e- collisions and their two-NBD fits. Moments of the multiplicity distribution in a two-NBD model for 1.8 TeV pp collisions are considered. Three-NBD model predictions and fits for pp at LHC energies are also discussed. Analytic expressions for moments of hybrid NBD are derived and used to get insight into jet parameters and multicomponent structure of the processes. Interpretation of observed correlations is proposed.Comment: 8 pages, no figures, Phys. Lett.

Soft Gluon kt-Resummation and the Froissart bound

We study soft gluon kt-resummation and the relevance of zero momentum gluons for the energy dependence of total hadronic cross-sections. We discuss a model in which consistency of the energy dependence of the cross-section with the limitation of the Froissart bound, is directly related to the behaviour of the strong coupling constant in the infrared region. Our predictions for the asymptotic behaviour are shown to be related to the ansatz that the infrared behaviour of the QCD strong coupling constant follows an inverse power law.Comment: To be published in Physics Letters B. This version is 25% shorter than the previous one, as requested by the restrictions on the number of pages for this Journal. Some equations have been skipped, some text has been summarized. The earliest version may be useful for a better understanding of some of the materia