Proton-Proton Physics with ALICE

The goal of the ALICE experiment at LHC is to study strongly interacting matter at high energy densities as well as the signatures and properties of the quark-gluon plasma. This goal manifests itself in a rich physics program. Although ALICE will mainly study heavy-ion collisions, a dedicated program will concentrate on proton-proton physics. The first part will introduce the ALICE experiment from a pp measurement's point of view. Two unique properties are its low pT cut-off and the excellent PID capabilities. The various topics of the proton-proton physics program, which will allow a close scrutiny of existing theoretical models, will be described. Furthermore, the interpretation of measurements of heavy-ion collisions necessitates the comparison to measurements of pp collisions. The second part will concentrate on the day-1 physics program of ALICE. At startup, neither the LHC luminosity nor its energy will have their nominal values. Furthermore, the ALICE detector is in the process of being aligned and calibrated. Still several physics topics can be studied from the very beginning. These will be presented as well as the effort that is already ongoing to be ready for the first collision. The statistics needed for each of the topics will be given with respect to the foreseen LHC startup scenario.Comment: Contribution for the 1st International Workshop on Soft Physics in ultrarelativistic Heavy Ion Collisions, Catania, Italy, 200

Measuring the Charged Particle Multiplicity with ALICE

The charged particle multiplicity distribution is one of the first measurements that ALICE will be able to perform. The knowledge of this basic property at a new energy is needed to configure Monte Carlo generators correctly with the aim of understanding the background of other, especially rare, processes including new physics. It allows to study the scaling behaviour and to verify model predictions. The unfolding of the measurement is a non-trivial task due to the finite precision and acceptance of the detector. Solutions are based on chi2 minimization or iteratively using Bayes' theorem. Both approaches to unfold the spectrum are presented. Furthermore, the capabilities of the SPD fast OR trigger are shown that enable physics at very high multiplicities.Comment: Proceedings of poster presentation at Quark Matter 2008, 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions in Jaipur, India; to be published in Indian Journal of Physics; 4 pages, 4 figure

Theoretical and Experimental Considerations for Neutrinoless Double Beta Decay

In the rst part of this work we show some theoretical aspects of the generation of the neutrino mass by means of a direct extension of the Standard Model of particles, which include the presence of heavy right-handed neutrinos and large Majorana mass terms. From these two new ingredients, it is possible to nd a mass for the light neutrinos which is naturally of the order of 1 eV or less. The idea is to put these theoretical aspects in the context of the search for neutrino mass values by the study of the signal from the Neutrinoless Double Beta Decay Process (0 ). In the second part, a brief summary is given of the experimental considerations required for the measurement of effective Majorana neutrino mass using (0 ). Measurement strategies and background considerations are introduced and an outline of both active and passive methods is given. Finally, current results are discussed with particular emphasis on the HeidelbergMoscow experiment. This note is based on the presentation given at the CERNCLAF 4th Latin American School on High-Energy Physics

ALICE results from the first Pb-Pb run at the CERN LHC

After 20 years of preparation, the dedicated heavy ion experiment ALICE took first data at the CERN LHC accelerator with proton collisions at the end of 2009 and with lead beams at the end of 2010. This article will give a brief overview of the main results presented at the Quark Matter 2011 conference.Comment: Inited talk at the 22nd International Conference on Ultra-relativistic Nucleus-Nucleus Collision (Quark Matter 2011), 23 - 28 May 2011, Annecy, Franc

Charged-Particle Multiplicity in Proton-Proton Collisions

This article summarizes and critically reviews measurements of charged-particle multiplicity distributions and pseudorapidity densities in p+p(pbar) collisions between sqrt(s) = 23.6 GeV and sqrt(s) = 1.8 TeV. Related theoretical concepts are briefly introduced. Moments of multiplicity distributions are presented as a function of sqrt(s). Feynman scaling, KNO scaling, as well as the description of multiplicity distributions with a single negative binomial distribution and with combinations of two or more negative binomial distributions are discussed. Moreover, similarities between the energy dependence of charged-particle multiplicities in p+p(pbar) and e+e- collisions are studied. Finally, various predictions for pseudorapidity densities, average multiplicities in full phase space, and multiplicity distributions of charged particles in p+p(pbar) collisions at the LHC energies of sqrt(s) = 7 TeV, 10 TeV, and 14 TeV are summarized and compared.Comment: Invited review for Journal of Physics G -- version 2: version after referee's comment

Anisotropic flow at the LHC measured with the ALICE detector

The ALICE detector at the LHC recorded first Pb-Pb collisions at 2.76 TeV in November and December of 2010. We report on the measurements of anisotropic flow for charged and identified particles. From the comparison with measurements at lower energies and with model predictions we find that the system created at these collision energies is described well by hydrodynamical model calculations and behaves like an almost perfect fluid.Comment: 8 pages, 16 figures, plenary talk at Quark Matter 2011, May 23rd-28th 2011, Annecy, Franc

Consequences of temperature fluctuations in observables measured in high energy collisions

We review the consequences of intrinsic, nonstatistical temperature fluctuations as seen in observables measured in high energy collisions. We do this from the point of view of nonextensive statistics and Tsallis distributions. Particular attention is paid to multiplicity fluctuations as a first consequence of temperature fluctuations, to the equivalence of temperature and volume fluctuations, to the generalized thermodynamic fluctuations relations allowing us to compare fluctuations observed in different parts of phase space, and to the problem of the relation between Tsallis entropy and Tsallis distributions. We also discuss the possible influence of conservation laws on these distributions and provide some examples of how one can get them without considering temperature fluctuations.Comment: Revised version of the invited contribution to The European Physical Journal A (Hadrons and Nuclei) topical issue about 'Relativistic Hydro- and Thermodynamics in Nuclear Physics' guest eds. Tamas S. Biro, Gergely G. Barnafoldi and Peter Va