Blast-wave model description of the Hanbury-Brown--Twiss radii in pp collisions at LHC energies

The blast wave model is applied to the recent data on HBT radii in pp collisions, measured by the ALICE collaboration. A reasonable description of data is obtained for a rather low temperature of the kinetic freeze-out, T ~ 100 MeV, and the transverse profile corresponding to the emission from a shell of a fairly small width 2 d ~ 1.5 fm. The size and the life-time of the produced system are determined for various multiplicities of the produced particles.Comment: version published in J. Phys.

Finite size of hadrons and Bose-Einstein correlations in pppp collisions at 7 TeV

Space-time correlations between produced particles, induced by the composite nature of hadrons, imply specific changes in the properties of the correlation functions for identical particles. The expected magnitude of these effects is evaluated using the recently published blast-wave model analysis of the data for $pp$ collisions at $\sqrt{s}$ = 7 TeV.Comment: The updated version matching the published PLB articl

Bose-Einstein correlations and thermal cluster formation in high-energy collisions

The blast wave model is generalized to include the production of thermal clusters, as suggested by the apparent success of the statistical model of particle production at high energies. The formulae for the HBT correlation functions and the corresponding HBT radii are derived.Comment: minor text corrections, a few references added, version accepted for publication in APP

Implementation of On-Line Data Reduction Algorithms in the CMS Endcap Preshower Data Concentrator Card

The CMS Endcap Preshower (ES) sub-detector comprises 4288 silicon sensors, each containing 32 strips. The data are transferred from the detector to the counting room via 1208 optical fibres running at 800Mbps. Each fibre carries data from 2, 3 or 4 sensors. For the readout of the Preshower, a VME-based system - the Endcap Preshower Data Concentrator Card (ES-DCC) is currently under development. The main objective of each readout board is to acquire on-detector data from up to 36 optical links, perform on-line data reduction (zero suppression) and pass the concentrated data to the CMS event builder. This document presents the conceptual design of the Reduction Algorithms as well as their implementation into the ES-DCC FPGAs. The algorithms implemented into the ES-DCC resulted in a reduction factor of ~20

GLISSANDO: GLauber Initial-State Simulation AND mOre

GLISSANDO is a Glauber Monte-Carlo generator for early-stages of relativistic heavy-ion collisions, written in c++ and interfaced to Root. Several models are implemented: the wounded-nucleon model, the binary collisions model, the mixed model, and the model with hot-spots. Subtleties of the distribution of nucleon in the nucleus are discussed. The original geometric distribution of sources in the transverse plane can be superimposed with a statistical distribution simulating the dispersion in the generated transverse energy in each individual collision. The program generates inter alia the fixed axes (standard) and variable-axes (participant) two-dimensional profiles of the density of sources in the transverse plane and their Fourier components. These profiles can be used in further analyses of physical phenomena, such as the the jet quenching, event-by-event hydrodynamics, or analysis of the elliptic flow and its fluctuations. Characteristics of the event (multiplicities, eccentricities, Fourier coefficients, etc.) are evaluated and stored in a file for further off-line studies. A number of scripts is provided for that purpose. Supplied variants of the code can also be used for the proton-nucleus and deuteron-nucleus collisions.Comment: Updated ver. 1.6 of the code available at http://www.pu.kielce.pl/homepages/mryb/GLISSANDO

Highly-anisotropic and strongly-dissipative hydrodynamics with transverse expansion

A recently formulated framework of highly-anisotropic and strongly-dissipative hydrodynamics (ADHYDRO) is used to describe the evolution of matter created in ultra-relativistic heavy-ion collisions. New developments of the model contain: the inclusion of asymmetric transverse expansion (combined with the longitudinal boost-invariant flow) and comparisons of the model results with the RHIC data, which have become possible after coupling of ADHYDRO with THERMINATOR. Various soft-hadronic observables (the transverse-momentum spectra, the elliptic flow coefficient v_2, and the HBT radii) are calculated for different initial conditions characterized by the value of the initial pressure asymmetry. We find that as long as the initial energy density profile is unchanged the calculated observables remain practically the same. This result indicates the insensitivity of the analyzed observables to the initial anisotropy of pressure and suggests that the complete thermalization of the system may be delayed to easily acceptable times of about 1 fm/c

The CMS Electromagnetic Calorimeter Data Acquisition System at the 2006 Test Beam

The Electromagnetic Calorimeter of the CMS experiment at the CERN LHC is an homogeneous calorimeter made of about 80000 Lead Tungstate crystals. From June to November 2006, eleven barrel Supermodules (1700 crystals each) were exposed to beam at CERN SPS, both in stand-alone and in association with portions of the Hadron Calorimeter. We present the description of the system used to configure and readout the calorimeter during this period. The full set of final readout electronics boards was employed, together with the pre-series version of the data acquisition software. During this testbeam, the hardware and software concepts for the final system were validated and the successfull operation of all the ten supermodules was ensured