RPC with low-resistive phosphate glass electrodes as a candidate for the CBM TOF

Usage of electrodes made of glass with low bulk resistivity seems to be a promising way to adapt the Resistive Plate Chambers (RPC) to the high-rate environment of the upcoming CBM experiment. A pilot four-gap RPC sample with electrodes made of phosphate glass, which has bulk resistivity in the order of 10^10 Ohm cm, has been studied with MIP beam for TOF applications. The tests have yielded satisfactory results: the efficiency remains above 95% and the time resolution stays within 120 ps up to the particle rate of 18 kHz/cm2. The increase in rate from 2.25 to 18 kHz/cm2 leads to an increase of estimated "tails" fraction in the time spectrum from 1.5% to 4%.Comment: 8 pages, 6 figures, submitted to Elsevier Scienc

Multiplicity Studies and Effective Energy in ALICE at the LHC

In this work we explore the possibility to perform ``effective energy'' studies in very high energy collisions at the CERN Large Hadron Collider (LHC). In particular, we focus on the possibility to measure in $pp$ collisions the average charged multiplicity as a function of the effective energy with the ALICE experiment, using its capability to measure the energy of the leading baryons with the Zero Degree Calorimeters. Analyses of this kind have been done at lower centre--of--mass energies and have shown that, once the appropriate kinematic variables are chosen, particle production is characterized by universal properties: no matter the nature of the interacting particles, the final states have identical features. Assuming that this universality picture can be extended to {\it ion--ion} collisions, as suggested by recent results from RHIC experiments, a novel approach based on the scaling hypothesis for limiting fragmentation has been used to derive the expected charged event multiplicity in $AA$ interactions at LHC. This leads to scenarios where the multiplicity is significantly lower compared to most of the predictions from the models currently used to describe high energy $AA$ collisions. A mean charged multiplicity of about 1000-2000 per rapidity unit (at $\eta \sim 0$) is expected for the most central $Pb-Pb$ collisions at $\sqrt{s_{NN}} = 5.5 TeV$.Comment: 12 pages, 19 figures. In memory of A. Smirnitski

Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

Study of QGP signatures with the phi->K+K- signal in Pb-Pb ALICE events

The phi->K+K- decay channel in Pb-Pb collisions at LHC is studied through a full simulation of the ALICE detector. The study focuses on possible signatures in this channel of quark-gluon plasma (QGP) formation. On a basis of 10^6 collisions at high centrality some proposed QGP signatures are clearly visible both in K+K- invariant mass and transverse mass distributions. The high significance of this observation appears to reside heavily on the use of the TOF (Time Of Flight) system of ALICE in addition to its central tracking detectors.Comment: 9 pages, 7 figures, to appear in EPJ

First proton-proton collisions at the LHC as observed with the ALICE detector: measurement of the charged-particle pseudorapidity density at root s=900 GeV

On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in both the longitudinal and transverse directions and 284 events were recorded in coincidence with the two passing proton bunches. The events were immediately reconstructed and analyzed both online and offline. We have used these events to measure the pseudorapidity density of charged primary particles in the central region. In the range vertical bar eta vertical bar S collider. They also illustrate the excellent functioning and rapid progress of the LHC accelerator, and of both the hardware and software of the ALICE experiment, in this early start-up phase

Research on the Brand Building of Airways in China ——Brand Building of Pengda Airlines as an Example

面对经济全球化的浪潮，天空开放已经成为世界航空业的必然趋势，市场、资本、政策的壁垒正在逐步被打破，这既是机遇也是挑战。中国民航经过近年来规模的快速增长，已经奠定了世界民航大国的地位，与此同时，由于市场化程度低、产品同质化，民族航空业的国际竞争力仍有待大力提升。 纵观世界民航发展史，不论是新航、英航等行业常青树，还是捷蓝、维珍等行业新星，无不是以自身独特的价值屹立于世界航空之林，受到消费者的青睐和追捧，而这一独特价值的集中表现就是——品牌，品牌是一个企业基业常青的载体和象征。 本文结合先进的品牌理念和科学的管理工具，剖析民航行业发展态势和航空公司经营特征，以鹏达航空公司的品牌建设为例，从鹏航...In the face of economic globalization, the sky opening up, has become an inevitable trend in the global aviation industry, market, capital and policy barriers are gradually being broken, which is both an opportunity and a challenge. The scale of China's civil aviation through the rapid growth in recent years has laid the world's great power status of civil aviation, while the low level of the mark...学位：文学硕士院系专业：新闻传播学院新闻学系_新闻学学号：1052008115316

Algorithms and methods for particle identification with ALICE TOF detector at a very high particle multiplicity

The algorithms and methods for particle identification with ALICE TOF detector at a very high particle multiplicity were studied. The matching of the information acquired by TOF with the tracking data were realized by using the Kalman filtering method. The study showed that all the tracking and timing information enabled the particle identification (PID). (Edited abstract) 7 Refs

EbyE identified particle spectra and K/pi ratios using the TOF information

The latest simulations of PID efficiency and contamination have been applied to individual events generated by SHAKER and HIJING to build identified particle spectra. These spectra have been used to extract the inverse slopes for individual events for pi±, K± and pp' well as the K/pi ratios. The results obtained studying 25 events are shown

Influence of pixel occupancy on particle identification efficiency and contamination in ALICE TOF

momentum of the particles... Figure 13: The dependence of the efficiency and the contamination of track matching on the length of the pixel... Figure 14: The dependence of the efficiency and the contamination of track matching on pixel occupancy for SHAKER... Figure 15: The dependence of the efficiency and the contamination of track matching on pixel occupancy for SHAKER and HIJING generators... Figure 16: The dependence of the efficiency and the contamination of track matching on pixel occupancy for different input charged particle densities dNch/dy of SHAKER... Figure 17: The dependence of the efficiency and the contamination of track matching on pixel occupancy for two radius of the TPC... Figure 18: The dependence of the efficiency and the contamination of track matching on pixel occupancy for two values of the TPC thickness... Figure 19: The dependence of the efficiency and the contamination of track matching on pixel occupancy for two radius of TOF... Figure 20: Mass separation obtained from the TOF barrel (sigma=100ps) for electrons, pions, kaons and protons as a function of momentum ( 3 SHAKER events). Figure 21: Efficiency and contamination of PID vs momentum... Figure 22: Efficiency and contamination of PID vs occupancy... </UL