O. Kodolova

This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies , will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction — Quantum Chromodynamics (QCD) — in extreme conditions of temperature, density and parton momentum fraction (low-x).

The $\eta \pi^{-}$ system has been studied in the reaction $\pi^{-} p \to \eta \pi^{-} p$ at 18 GeV/c. A large asymmetry in the angular distribution is observed indicating interference between L-even and L-odd partial waves. The $a_{2}(1320)$ is observed in the $J^{PC}$ = $2^{++}$ wave, as is a broad enhancement between 1.2 and 1.6 GeV/c^{2} in the $J^{PC} = 1^{-+}$ wave. The observed phase difference between these waves shows that there is phase motion in addition to that due to $a_{2}(1320)$ decay. The data can be fitted by interference between the $a_{2}(1320)$ and an exotic $1^{-+}$ resonance with $M = (1370 \pm 16 {+50}\atop{-30}$) MeV/c^2 and $\Gamma =(385 \pm 40 {+65}\atop{-105}$) MeV/c^2.

A partial-wave analysis of the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}p$ at $18\mathrm{GeV}/c$ has been performed on a data sample of 250 000 events obtained by Brookhaven experiment E852. The expected ${J}^{\mathrm{PC}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1}^{++}{a}_{1}(1260)$, ${2}^{++}{a}_{2}(1320)$, and ${2}^{\ensuremath{-}+}{\ensuremath{\pi}}_{2}(1670)$ resonant states are clearly observed. The exotic ${J}^{\mathrm{PC}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1}^{\ensuremath{-}+}$ wave produced in the natural parity exchange processes shows distinct resonancelike phase motion at about $1.6\mathrm{GeV}{/c}^{2}$ in the $\ensuremath{\rho}\ensuremath{\pi}$ channel. A mass-dependent fit results in a resonance mass of $1593\ifmmode\pm\else\textpm\fi{}{8}_{\ensuremath{-}47}^{+29}\mathrm{MeV}{/c}^{2}$ and a width of $168\ifmmode\pm\else\textpm\fi{}{20}_{\ensuremath{-}12}^{+150}\mathrm{MeV}{/c}^{2}$.

An amplitude analysis of an exclusive sample of 5765 events from the reaction π−p→η′π−p at 18GeV/c is described. The η′π− production is dominated by natural parity exchange and by three partial waves: those with JPC=1−+, 2++, and 4++. A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a2(1320) meson as well as the a4(2040) meson, observed for the first time decaying to η′π−. The dominant, exotic (non- q¯q) 1−+ partial wave is shown to be resonant with a mass of 1.597±0.010+0.045−0.010GeV/c2 and a width of 0.340±0.040±0.050GeV/c2. This exotic state, the π1(1600), is produced with a t dependence which is different from that of the a2(1320) meson, indicating differences between the production mechanisms for the two states.Received 2 February 2001DOI:https://doi.org/10.1103/PhysRevLett.86.3977©2001 American Physical Society

This Letter reports results from the partial wave analysis of the π−π−π+η final state in π−p collisions at 18GeV/c. Strong evidence is observed for production of two mesons with exotic quantum numbers of spin, parity and charge conjugation, JPC=1−+ in the decay channel f1(1285)π−. The mass M=1709±24±41MeV/c2 and width Γ=403±80±115MeV/c2 of the first state are consistent with the parameters of the previously observed π1(1600). The second resonance with mass M=2001±30±92MeV/c2 and width Γ=333±52±49MeV/c2 agrees very well with predictions from theoretical models. In addition, the presence of π2(1900) is confirmed with mass M=2003±88±148MeV/c2 and width Γ=306±132±121MeV/c2 and a new state, a1(2096), is observed with mass M=2096±17±121MeV/c2 and width Γ=451±41±81MeV/c2. The decay properties of these last two states are consistent with flux tube model predictions for hybrid mesons with non-exotic quantum numbers.

We report on the test beam results and calibration methods using high energy electrons, pions and muons with the CMS forward calorimeter (HF). The HF calorimeter covers a large pseudorapidity region ( $3\leq|\eta|\leq5$ ), and is essential for a large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of forward tagging jets in weak boson fusion channels in Higgs production. The HF calorimeter is based on steel absorber with embedded fused-silica-core optical fibers where Cherenkov radiation forms the basis of signal generation. Thus, the detector is essentially sensitive only to the electromagnetic shower core and is highly non-compensating (e/h≈5). This feature is also manifest in narrow and relatively short showers compared to similar calorimeters based on ionization. The choice of fused-silica optical fibers as active material is dictated by its exceptional radiation hardness. The electromagnetic energy resolution is dominated by photoelectron statistics and can be expressed in the customary form as $\frac{a}{\sqrt{E}}\oplus{b}$ . The stochastic term a is 198% and the constant term b is 9%. The hadronic energy resolution is largely determined by the fluctuations in the neutral pion production in showers, and when it is expressed as in the electromagnetic case, a = 280% and b = 11%.

A partial-wave analysis of the mesons from the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}p$ has been performed. The data show ${b}_{1}\ensuremath{\pi}$ decay of the spin-exotic states ${\ensuremath{\pi}}_{1}(1600)$ and ${\ensuremath{\pi}}_{1}(2000)$. Three isovector ${2}^{\ensuremath{-}+}$ states were seen in the $\ensuremath{\omega}{\ensuremath{\rho}}^{\ensuremath{-}}$ decay channel. In addition to the well known ${\ensuremath{\pi}}_{2}(1670)$, signals were also observed for ${\ensuremath{\pi}}_{2}(1880)$ and ${\ensuremath{\pi}}_{2}(1970)$.

Details of the analysis of the ηπ− system studied in the reaction π−→pηπ−p at 18GeV/c are given. Separate analyses for the 2γ and π+π−π0 decay modes of the η are presented. An amplitude analysis of the data indicates the presence of interference between the a−2(1320) and a JPC=1−+ wave between 1.2 and 1.6GeV/c2. The phase difference between these waves shows a phase motion not attributable solely to the a−2(1320). The data can be fitted by interference between the a−2(1320) and an exotic 1−+ resonance with M=(1370±16+50−30)MeV/c2 and Γ=(385±40+65−105)MeV/c2. Our results are compared with those of other experiments.Received 13 January 1999DOI:https://doi.org/10.1103/PhysRevD.60.092001©1999 American Physical Society

The mass and width of the a0(980) have been independently determined from a nearly background free data sample and the coupling constants to the eta-pi and K-K-bar modes have been determined

A partial-wave analysis of the reaction π−→pπ+π−π−p at 18GeV/c has been performed on a data sample of 250 000 events obtained in the Brookhaven experiment E852. The well-known a1(1260), a2(1320) and π2(1670) resonant states are observed. The existence of the π(1800), a1(1700) and a4(2040) states is confirmed. The a3(1874) state is also observed. The exotic 1−+ π1(1600) state produced in the natural parity exchange process is found to decay in the ρ(770)π− channel. A mass-dependent fit results in a resonance mass of 1593±8+29−47MeV/c2 and a width of 168±20+150−12MeV/c2. Received 19 November 2001DOI:https://doi.org/10.1103/PhysRevD.65.072001©2002 American Physical Society

Extensive measurements have been made with pions, electrons and muons on four production wedges of the compact muon solenoid (CMS) hadron barrel (HB) calorimeter in the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics running at 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers in the HB. The energy dependent time slewing effect was measured and tuned for optimal performance.

The exclusive reaction π−p→ηπ0n, η→π+π−π0 at 18GeV/c has been studied with a partial wave analysis on a sample of 23 492 ηπ0n events from BNL experiment E852. A mass-dependent fit is consistent with a resonant hypothesis for the P+ wave, thus providing evidence for a neutral exotic meson with JPC=1−+, a mass of 1257±20±25MeV/c2, and a width of 354±64±60MeV/c2. New interpretations of the meson exotics in neutral ηπ0 system observed in E852 and Crystal Barrel experiments are discussed.

A partial wave analysis of the π0π0 system produced in the charge exchange reaction π−p→π0π0n at an incident momentum of 18.3 GeV/c is presented as a function of the π0π0 invariant mass mπ0π0 and momentum transfer squared |t| from the incident π− to the outgoing π0π0 system. For small values of |t|, the S-wave intensity shows a broad enhancement at low mπ0π0 with a sharp dip in the vicinity of the f0(980). A dip is also observed in the vicinity of the f0(1500). There is a rapid variation of the S to D0 relative phase difference in these mass regions. For large values of |t|, the f0(980) appears as a bump. The f2(1270), observed in D waves, is produced dominantly by π exchange at low values of |t| and a2 exchange at higher values of |t|.Received 12 January 2000DOI:https://doi.org/10.1103/PhysRevD.64.072003©2001 American Physical Society

A 3045 element lead glass calorimeter and an associated fast trigger processor have been constructed, tested and implemented in BNL experiment E852 in conjunction with the multi-particle spectrometer (MPS). Approximately, 109 all-neutral and neutral plus charged triggers were recorded with this apparatus during data runs in 1994 and 1995. This paper reports on the construction, testing and performance of this lead glass calorimeter and the associated trigger processor.

We present the results from the heavy quarks and quarkonia working group. This report gives benchmark heavy quark and quarkonium cross sections for $pp$ and $pA$ collisions at the LHC against which the $AA$ rates can be compared in the study of the quark-gluon plasma. We also provide an assessment of the theoretical uncertainties in these benchmarks. We then discuss some of the cold matter effects on quarkonia production, including nuclear absorption, scattering by produced hadrons, and energy loss in the medium. Hot matter effects that could reduce the observed quarkonium rates such as color screening and thermal activation are then discussed. Possible quarkonium enhancement through coalescence of uncorrelated heavy quarks and antiquarks is also described. Finally, we discuss the capabilities of the LHC detectors to measure heavy quarks and quarkonia as well as the Monte Carlo generators used in the data analysis.

In this paper we present the Experiment Dashboard monitoring system, which is currently in use by four Large Hadron Collider (LHC)[1] experiments. The goal of the Experiment Dashboard is to monitor the activities of the LHC experiments on the distributed infrastructure, providing monitoring data from the virtual organization (VO) and user perspectives. The LHC experiments are using various Grid infrastructures (LCG[2]/EGEE[3], OSG[4], NDGF[5]) with correspondingly various middleware flavors and job submission methods. Providing a uniform and complete view of various activities like job processing, data movement and publishing, access to distributed databases regardless of the underlying Grid flavor is the challenging task. In this paper we will describe the Experiment Dashboard concept, its framework and main monitoring applications.

The reaction π−p→ωπ−p, ω→π+π−π0 has been studied at 18 GeV/c. The ωπ− mass spectrum is found to be dominated by the b1(1235). Partial Wave Analysis (PWA) shows that b1 production is dominated by natural parity exchange. The S-wave and D-wave amplitudes for b1(1235)→ωπ have been determined, and it is found that the amplitude ratio, |D/S|=0.269±(0.009)stat±(0.01)sys and the phase difference, φ(D−S)=10.54°±(2.4°)stat±(3.9°)sys.

Results are presented on a partial wave analysis of the ωη final state produced in π−p interactions at 18 GeV/c where ω→π+π−π0, π0→2γ , and η→2γ. We observe the previously unreported decay mode ω(1650)→ωη and a new 1+− meson state h1(1595) with a mass M=1594(±15) +10−60 MeV/c2 and a width Γ=384(±60) +70−100 MeV/c2. The h1(1595) state exhibits resonant-like phase motion relative to the ω(1650).

The number of pseudoscalar mesons in the mass range from 1400 to 1500 MeV/c2 has been a subject of considerable interest for many years, with several experiments having presented evidence for two closely spaced states. A new measurement of the reaction π−p→K+K−π0n has been made at a beam energy of 18 GeV. A partial wave analysis of the K+K−π0 system shows evidence for three pseudoscalar resonances, η(1295), η(1416), and η(1485), as well as two axial vectors, f1(1285), and f1(1420). Their observed masses, widths and decay properties are reported. No signal was observed for C(1480), an IGJPC=1+1−− state previously reported in φπ0 decay.

We discuss the importance of high-pT hadron and jet measurements in nucleus-nucleus collisions at the CERN Large Hadron Collider.

Abstract A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in π p interactions. We describe the chamber's design considerations, details of its construction, electronics, and performance characteristics.

A partial-wave analysis of 9082 $\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}n$ events produced in the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}n$ at $18.3 \mathrm{GeV}/c$ has been carried out using data from experiment 852 at Brookhaven National Laboratory. The data are dominated by ${J}^{\mathrm{PC}}{=0}^{\ensuremath{-}+}$ partial waves consistent with observation of the $\ensuremath{\eta}(1295)$ and the $\ensuremath{\eta}(1440).$ The mass and width of the $\ensuremath{\eta}(1295)$ were determined to be $1282\ifmmode\pm\else\textpm\fi{}5 \mathrm{MeV}$ and $66\ifmmode\pm\else\textpm\fi{}13 \mathrm{MeV},$ respectively, while the $\ensuremath{\eta}(1440)$ was observed with a mass of $1404\ifmmode\pm\else\textpm\fi{}6 \mathrm{MeV}$ and a width of $80\ifmmode\pm\else\textpm\fi{}21 \mathrm{MeV}.$ Other partial waves of importance include the ${1}^{++}$ and the ${1}^{+\ensuremath{-}}$ waves. Results of the partial wave analysis are combined with results of other experiments to estimate ${f}_{1}(1285)$ branching fractions. These values are considerably different from current values determined without the aid of amplitude analyses.

The jet reconstruction algorithms and calibration techniq ues implemented in the CMS reconstruction software are studied with high-statistics Monte Carlo samples of QCD dijet events. Generated events are passed through a full detector-level simulation of the CMS detector including readout digitization in the presence of pile-up at an instantaneous luminosity of L = 2×10 33 cm 2 s 1 . Effects of detector resolution and granularity on the jet resolutions, effic iencies and instrumental background rates are estimated. These measures of performance are compared for a set of jet algorithms, algorithm parameters, and calorimeter cell thresholds. The uniformity and linearity of the jet response are evaluated by comparing particle-level and reconstructed jets over a wide range of transverse momenta throughout the angular coverage of the calorimeters. Fits to the ratio o f reconstructed to generated jet transverse energy give a transverse energy resolution of 10-15% (8-10%) at 100 GeV (200 GeV) over the pseudorapidity range 0 < |�| < 5. The angular resolution for 100 GeV (200 GeV) jets is 0.02-0.035 (0.02) radians.

A partial-wave analysis of the reaction π−p→ηηπ−p at 18 GeV/c has been performed on a data sample of approximately 4000 events obtained by Brookhaven experiment E852. The JPC=0−+π(1800) state is observed in the a0(980)η and f0(1500)π decay modes. It has a mass of 1876±18±16 MeV/c2 and a width of 221±26±38 MeV/c2. The JPC=2−+π2(1880) meson is observed decaying through a2(1320)η. It has a mass of 1929±24±18 MeV/c2 and a width of 323±87±43 MeV/c2. Both states are potential candidates for non-exotic hybrid mesons.

Various pion and photon production mechanisms in high-energy nuclear collisions at RHIC and LHC are discussed. Comparison with RHIC data is done whenever possible. The prospect of using electromagnetic probes to characterize quark-gluon plasma formation is assessed...

The PMTs of the CMS Hadron Forward calorimeter were found to generate a large size signal when their windows were traversed by energetic charged particles. This signal, which is due to Čerenkov light production at the PMT window, could interfere with the calorimeter signal and mislead the measurements. In order to find a viable solution to this problem, the response of four different types of PMTs to muons traversing their windows at different orientations is measured at the H2 beam-line at CERN. Certain kinds of PMTs with thinner windows show significantly lower response to direct muon incidence. For the four anode PMT, a simple and powerful algorithm to identify such events and recover the PMT signal using the signals of the quadrants without window hits is also presented. For the measurement of PMT responses to Čerenkov light, the Hadron Forward calorimeter signal was mimicked by two different setups in electron beams and the PMT performances were compared with each other. Superior performance of particular PMTs was observed.

The CMS experiment at CERN is preparing for LHC data taking in several computing preparation activities. In early 2007 a traffic load generator infrastructure for distributed data transfer tests was designed and deployed to equip the WLCG tiers which support the CMS virtual organization with a means for debugging, load-testing and commissioning data transfer routes among CMS computing centres. The LoadTest is based upon PhEDEx as a reliable, scalable data set replication system. The Debugging Data Transfers (DDT) task force was created to coordinate the debugging of the data transfer links. The task force aimed to commission most crucial transfer routes among CMS tiers by designing and enforcing a clear procedure to debug problematic links. Such procedure aimed to move a link from a debugging phase in a separate and independent environment to a production environment when a set of agreed conditions are achieved for that link. The goal was to deliver one by one working transfer routes to the CMS data operations team. The preparation, activities and experience of the DDT task force within the CMS experiment are discussed. Common technical problems and challenges encountered during the lifetime of the taskforce in debugging data transfer links in CMS are explained and summarized.

We present the inclusive and semi-inclusive spectra of charged particles in pp and p\ifmmode\bar\else\textasciimacron\fi{}p interactions at an incident projectile momentum of 32 GeV/c, based on the full statistics of both experiments and obtained by means of the liquid hydrogen bubble chamber MIRABELLE at the Serpukhov accelerator. The spectra of charged particles are separated by a statistical method in the whole kinematically allowed region of phase space. Both inclusive and semi-inclusive cross sections of ${\mathrm{\ensuremath{\pi}}}^{\ifmmode\pm\else\textpm\fi{}}$, p, and ${\mathit{K}}^{\mathrm{\ensuremath{-}}}$ production in pp interactions are given. The differential cross sections are studied in terms of the Feynman variable x, rapidity, and transverse momentum. The results obtained strongly support the conclusion of the similarity of multiparticle production processes in pp and nonannihilation p\ifmmode\bar\else\textasciimacron\fi{}p interactions. It is shown that the soft pp and p\ifmmode\bar\else\textasciimacron\fi{}p interactions at the energies in question can be described at the quark-parton level in the framework of the quark-gluon string model. The derived particle spectra are compared with those at neighboring energies. The results of different phenomenological fits, including the hydrodynamical model predictions, are also listed.

Job processing and data transfer are the main computing activities on the WLCG infrastructure. Reliable monitoring of the job processing on the WLCG scope is a complicated task due to the complexity of the infrastructure itself and the diversity of the currently used job submission methods. The paper will describe current status and the new strategy for the job monitoring on the WLCG scope, covering primary information sources, job status changes publishing, transport mechanism and visualization.

The CMS experiment is preparing for LHC data taking in several computing preparation activities. In distributed data transfer tests, in early 2007 a traffic load generator infrastructure was designed and deployed, to equip the WLCG Tiers which support the CMS Virtual Organization with a means for debugging, load-testing and commissioning data transfer routes among CMS Computing Centres. The LoadTest is based upon PhEDEx as a reliable, scalable dataset replication system. In addition, a Debugging Data Transfers (DDT) Task Force was created to coordinate the debugging of data transfer links in the preparation period and during the Computing Software and Analysis challenge in 2007 (CSA07). The task force aimed to commission most crucial transfer routes among CMS tiers by designing and enforcing a clear procedure to debug problematic links. Such procedure aimed to move a link from a debugging phase in a separate and independent environment to a production environment when a set of agreed conditions are achieved for that link. The goal was to deliver one by one working transfer routes to Data Operations. The experiences with the overall test transfers infrastructure within computing challenges - as in the WLCG Common-VO Computing Readiness Challenge (CCRC’08) - as well as in daily testing and debugging activities are reviewed and discussed, and plans for the future are presented.

New measurements of peripheral meson production are presented. The data confirm the existence of exotic mesons at 1.4 and 1.6 GeV/c2. The latter state dominates the eta'pi- decay spectrum. The data on eta pi+pi-pi- decay show large strength in several exotic (Jpc = 1- +) waves as well.

The performance of a jet-energy-correction algorithm using reconstructed charged particle tracks is presented. The jet energy correction allows the jet energy scale to be restored and improves the energy resolution for jets with energies up to 120 GeV. For low energy jets (20 GeV) it improves the resolution by a factor 1.7 with respect to uncorrected jets. For 100 GeV jets the resolution improves by 15%. The deviation from unity of the ratio of the reconstructed to the generator jet transverse energies decreases by a factor two for low- $\rm E_{\rm T}$ jets ( $\rm E_{\rm T} < 30$ GeV). For high- $\rm E_{\rm T}$ jets, this ratio amounts to $1.00\pm0.04$ .

The expected performance of CMS for jet energy measurements is discussed. The use of the different calibration methods allows one to restore the linearity of the CMS calorimeter relative to jets and to improve the jet energy resolution.

The status of spin-exotic mesons is reviewed. There is now compelling evidence for at least three π1 states between one and two GeV. Preliminary results from the reaction π−p → π+π+π−π−π0p show structure in the exotic waves corresponding to IGJPC = 0−2+−.

The results of the model analysis of hadron femtoscopic correlations and factorial moments of particle multiplicity in heavy ion collisions for the energy range of the Beam Energy Scan (BES) program at RHIC and future NICA collider are presented. For this purpose, the simulation of Au+Au collisions at center-of-mass energies 7.7 and 11.5 GeV per nucleon pair using the UrQMD, vHLLE+UrQMD (with the crossover and first-order equation of states), and HYDJET++ event generators was performed. The sensitivity of pion and kaon correlation radii and the dependence of the factorial moments on heavy ion beam energy to quark–hadron phase transition details was studied. In addition, the possible influence of some relevant detector effects on the corresponding experimental observables is discussed.

The sensitivity of the jet transverse structure to the hadronization models (cluster and string hadronization models), expected for 10 pb-1 of integrated luminosity with the compact muon solenoid experiment at the large hadron collider, is determined. A new variable is developed and employed for this purpose: the second moment of the jet profile in the transverse momentum, which is calculated using particle tracks.

Various pion and photon production mechanisms in high-energy nuclear collisions at RHIC and LHC are discussed. Comparison with RHIC data is done whenever possible. The prospect of using electromagnetic probes to characterize quark-gluon plasma formation is assessed.

The production of quarkonia is one of the most promising signals at LHC for the study of the production properties of quark gluon plasma. In addition to J/ψ the extent to which is suppressed should give much insight into the new state of matter. The large muon acceptance and the high-precision tracker make the CMS detector ideal for studies of this physics. In this note, the performance of the CMS detector for quarkonia measurements in heavy-ion collisions in the dimuon channel is presented. Dimuon reconstruction efficiencies and mass resolution are calculated using detailed detector simulation. Mass spectra and signal to background ratios are estimated with a fast Monte Carlo program. Results obtained with the fast Monte Carlo program are compared with more detailed simulations.

The synchronization and timing of the hadron calorimeter (HCAL) for the Compact Muon Solenoid has been extensively studied with test beams at CERN during the period 2003-4, including runs with 40 MHz structured beam. The relative phases of the signals from different calorimeter segments are timed to 1 ns accuracy using a laser and equalized using programmable delay settings in the front-end electronics. The beam was used to verify the timing and to map out the entire range of pulse shapes over the 25 ns interval between beam crossings. These data were used to make detailed measurements of energy-dependent time slewing effects and to tune the electronics for optimal performance.

The Compact Muon Solenoid (CMS) is a high-performance general-purpose detector at the Large Hadron Collider (LHC) at CERN.More than twenty institutes from Russia and Joint Institute for Nuclear Research (JINR) are involved in Russia and Dubna Member States (RDMS) CMS Collaboration.A proper computing grid-infrastructure has been constructed at the RDMS institutes for the participation in the running phase of the CMS experiment.Current status of RDMS CMS computing and plans of its development to the next LHC start in 2015 are presented.

We present the capabilities of the CMS experiment to explore the heavy-ion physics program offered by the CERN Large Hadron Collider (LHC). The prime goal of this research is to test the fundamental theory of the strong interaction (QCD) in extreme conditions of temperature, density and parton momentum fraction by colliding nuclei at energies of √ s NN = 5.5 TeV. This presentation will give the overview of the potential of the CMS to carry out a full set of representative Pb-Pb measurements both in ”soft” and ”hard” regimes. Measurements include “bulk” observables ‐ charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow ‐ which provide information on the collective propertie s of the system; as well as perturbative processes ‐ such as quarkonia, heavy-quarks, jets, -jet, and high pT hadrons — which yield “tomographic” information of the hottest and densest phases of the reaction. 1. Understanding the strong force under extreme conditions The study of the strong interaction (QCD) in extreme conditions of temperature and density has been the driving force for experiments from the Bevalac to the the Large Hadron Collider. In the last decade the four RHIC experiments have produced beautiful evidence that in the energy range √ sNN = 63− 200 GeV a strongly interacting quark gluon liquid is produced [1]. The scaling of the elliptic flow with quark number, the suppressi on of fast quarks in the medium are clears signals of this but a great wealth of other evidence is shown in the proceedings of this conference. At both SPS and RHIC energies the suppression of the J/ resonance suggests that we have created a very high temperature system [2, 3, 4]. In addition there is evidence, from work at forward rapidities that at small parton momentum fraction (low-x) the initial state of the nuclei may be a sheet of gluons, the color glass condensate [5, 6]. The LHC plans to collide Pb nuclei at √ sNN = 5.5 TeV which is 28 times higher than the highest energy available at RHIC. We expect the initial state to be dominated by saturated parton distribution with relevant range of parton momentum fraction x as low as 10 −5 and a characteristic saturation momentum, Q 2≃ 5− 10 GeV 2 [7]. The collisions should produce copious hard probes such as jets, high- pT hadrons, heavy-quarks, quarkonia and large yields of the weakly interacting perturbative probes (direct photons, dileptons, Z 0 and W ± bosons) [8]. This paper will concentrate on our best guess of the physics at the LHC with an emphasis on early measurements. However the great strength of CMS is that it is a generic detector for heavy ions well suited to discovering the completely unexpected.

We will present the capabilities of the ATLAS and CMS experiments to explore the heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC).The collisions of lead nuclei at energies √ s NN = 5.5 TeV, will probe quark and gluon matter at unprecedented values of energy density.The prime goal of this research is to study the fundamental theory of the strong interaction (QCD) in extreme conditions of temperature, density and low parton momentum fraction.The current paper will give an overview of the potential of ATLAS and CMS to carry out a set of representative Pb-Pb measurements.These include "bulk" observables, like charged hadron multiplicity, low p T inclusive hadron identified spectra and elliptic flow -which provide information on the collective properties of the system; as well as perturbative processes, such as quarkonia, heavy-quarks, jets, γ-jet, and high p T hadrons -which yield "tomographic" information of the hottest and densest phases of the reaction.

We will present the capabilities of the ATLAS and CMS experiments to explore the heavy-ion physics programme in hard probes sector offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies √ sNN = 5.5 TeV, will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction (QCD) in extreme conditions of temperature, density and low parton momentum fraction. The current paper will give an overview of the potential of ATLAS and CMS to carry out a set of representative hard probes measurements with Pb–Pb beams. These include perturbative processes, such as quarkonia, heavy-quarks, jets, γ-jet, and high pT hadrons — which yield “tomographic” information of the hottest and densest phases of the reaction.

We will present the capabilities of the ATLAS and CMS experiments to explore the heavy-ion physics programme in hard probes sector offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies √ sNN = 5.5 TeV, will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction (QCD) in extreme conditions of temperature, density and low parton momentum fraction. The current paper will give an overview of the potential of ATLAS and CMS to carry out a set of representative hard probes measurements with Pb–Pb beams. These include perturbative processes, such as quarkonia, heavy-quarks, jets, γ-jet, and high pT hadrons — which yield “tomographic” information of the hottest and densest phases of the reaction.

We present the capabilities of the CMS experiment to explore the heavy-ion physics program offered by the CERN Large Hadron Collider (LHC).The prime goal of this research is to test the fundamental theory of the strong interaction (QCD) in extreme conditions of temperature, density and parton momentum fraction by colliding nuclei at energies of √ s NN = 5.5 TeV.This presentation will give the overview of the potential of the CMS to carry out a full set of representative Pb-Pb measurements both in "soft" and "hard" regimes.Measurements include "bulk" observables -charged hadron multiplicity, low p T inclusive hadron identified spectra and elliptic flow -which provide information on the collective properties of the system; as well as perturbative processes -such as quarkonia, heavy-quarks, jets, γ-jet, and high p T hadrons -which yield "tomographic" information of the hottest and densest phases of the reaction.

The space-time characteristics of particle production are measured by the correlation femtoscopy with use of quantum statistics (QS) and final state interactions (FSI) effects. Femtoscopy at lower energy was a key of importance at AGS, SPS and in the Beam Energy Scan (BES) physics program at RHIC. Using femtoscopy observables we investigate possibilities to observe a difference from the first-order phase transition expected, according to some theoretical predictions, at low energies and the cross over one, to be occurred at high energies. The hybrid model vHLLE+UrQM is used as a baseline for this study. The possibilities to use kaon femtoscopy complementary to the usually used pion one are discussed.

Abstract The main goal of heavy-ion collision measurements at NICA energies <?CDATA $(\sqrt{{s}_{NN}}=4-11\,{\rm{GeV}})$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mi>s</mml:mi><mml:mrow><mml:mi>N</mml:mi><mml:mi>N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>4</mml:mn><mml:mo>−</mml:mo><mml:mn>11</mml:mn><mml:mspace width="0.25em" /><mml:mi mathvariant="normal">GeV</mml:mi></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> is to study the properties of the quark-gluon matter at high baryon densities. Femtoscopy allows one to probe spatial and temporal characteristics of the particle-emission process at the last stage of the collision evolution - kinetic freeze-out. In this proceedings, we present estimations of like-sign pion and kaon pair femtoscopic observables for NICA energies using the UrQMD model. The dependence of the femtoscopic radii on collision energy, centrality, and pair transverse momentum are shown.

The recent search for non $q \bar{q}$ mesons in $π^{-}p$ interactions at Brookhaven National Laboratory is summarized. Many final states such as $ηπ$, $η' π^{-}$, $a_{0} π$, $f_{1} π$, $a_{2} π$, $b_{1} π$, which are favored decay modes of exotics, are under investigation.

A partial-wave analysis of the mesons from the reaction {pi}{sup -} p {yields} {pi}{sup +}{pi}{sup -}{pi}{sup -}{pi}{sup 0}{pi}{sup 0}p has been performed. The data show b{sub 1}{pi} decay of the spin-exotic states {pi}{sub 1}(1600) and {pi}{sub 1}(2000). Three isovector 2{sup -+} states were seen in the {omega}{rho}{sup -} decay channel. In addition to the well known {pi}{sub 2}(1670), signals were also observed for {pi}{sub 2}(1880) and {pi}{sub 2}(1970).

The Grid offers physicists far more resources than have previously available by combining elements in computing centers around the world into a globally accessible resource. In order to harness this available computing power many more steps need to be performed to package applications, locate data and control execution. The aim of the ASAP (ARDA Support for CMS Analysis Process) is to make this step as simple and straightforward for physicists on the CMS experiment at CERN. Starting from a local application and a configuration file ASAP can be used to transfer that application to the Grid by creating, submitting and monitoring jobs. One of the main components of this system is that users can delegate responsibility for their tasks to the ASAP Task Manager which can take actions on behalf of the user to ensure that tasks are completed successfully. Upwards of 30 physicists have used the system with 90,000 jobs submitted and 30 million events analysed every month.

The possibility to measure dimuons from Υ and J/Ψ families, hardjets And photons produced in ultra-relativistic heavy ion collisions at LHC energies have been investigated. The simulations were carried out for the CMS detector. A strong correlation between the transverse energy gathered in the calorimeters and event centrality is observed. The invariant mass spectrum for Pb-Pb events is presented and the signal to background ratios for Υ and J/Ψ masses are calculated. Expected statistics will be large enough to look for the correlations with centrality of events and transverse momentum of the resonance state. The jets and photons with E T > 100GeV will be measured with good efficiency and purity. γ-jet and Z-jet events give a good possibility to evaluate the energy losses of hard partons in dense matter.

During 2001/2002, the Russian Regional Center participates in CMS events production using Objectivity database. The common federation was created in two geographically remote sites in Moscow, SINP MSU and ITEP, connected by Gigabit Ethernet. Semi-automatic scripts for database management have been created. The database is used by physicists from many Russian institutes and CERN. We also discuss the experience of using such tools as GDMP in this environment.

Brookhaven Experiment E852 is an experiment in meson spectroscopy configured to detect final states interactions of π−p collisions in search for meson states incompatible with the constituent quark model. A description of the experimental apparatus and a general overview of the latest results is given.

An amplitude analysis of an exclusive sample of 5765 events from the reaction {pi}{sup -} p {yields} {eta}{prime}{pi}{sup -} p at 18 GeV/c is described. The {eta}{prime}{pi}{sup -} production is dominated by natural parity exchange and by three partial waves: those with J{sup PC} = 1{sup -+}, 2{sup ++}, and 4{sup ++}. A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a{sub 2}(1320) meson as well as the a{sub 4}(2040) meson, observed for the first time decaying to {eta}{prime}{pi}{sup -}. The dominant, exotic (non-q{bar q}) 1{sup -+} partial wave is shown to be resonant with a mass of 1.597 {+-} 0.010{sub -0.010}{sup +0.045} GeV/c{sup 2} and a width of 0.340 {+-} 0.040 {+-} 0.050 GeV/c{sup 2}. This exotic state, the {pi}{sub 1}(1600), is produced with a t dependence which is different from that of the a{sub 2}(1320) meson, indicating differences between the production mechanisms for the two states.

Transverse momentum imbalance between a jet produced with a hard photon is considered as a signal of medium-induced partonic energy loss in ultrarelativistic heavy ion collisions. We analyze photon-jet correlation in the context of a real experimental situation at the LHC, the problem of neutral pion background being discussed.

The reaction {pi}{sup -} p {yields} {omega}{pi}{sup -} p, {omega} {yields} {pi}{sup +} {pi}{sup -} {pi}{sup 0} has been studied at 18 GeV/c. The {omega}{pi}{sup -} mass spectrum is found to be dominated by the b{sub 1}(1235). Partial Wave Analysis shows that b{sub 1} production is dominated by natural parity exchange. The S-wave and D-wave amplitudes for b{sub 1}(1235) {yields} {omega}{pi} have been determined, and it is found that the amplitude ratio, |D/S| = 0.269 {+-} (0.009){sub stat} {+-} (0.01){sub sys} and the phase difference, {phi}(D-S) = 10.54{sup o} {+-} (2.4{sup o}){sub stat} {+-} (3.9){sub sys}.

A partial-wave analysis of the reaction pi{sup -}p-->pi{sup +}pi{sup -}pi{sup -}p at 18 GeV/c has been performed on a data sample of 250 000 events obtained in the Brookhaven experiment E852. The well-known a{sub 1}(1260), a{sub 2}(1320) and pi{sub 2}(1670) resonant states are observed. The existence of the pi(1800), a{sub 1}(1700) and a{sub 4}(2040) states is confirmed. The a{sub 3}(1874) state is also observed. The exotic 1{sup -+} pi{sub 1}(1600) state produced in the natural parity exchange process is found to decay in the rho(770)pi{sup -} channel. A mass-dependent fit results in a resonance mass of 1593{+-}8{sub -47}{sup +29} MeV/c{sup 2} and a width of 168{+-}20{sub -12}{sup +150} MeV/c{sup 2}.

A partial-wave analysis of the reaction {pi}{sup {minus}}p{r_arrow}{pi}{sup +}{pi}{sup {minus} }{pi}{sup {minus}}p at 18 GeV/c has been performed on a data sample of 250thinsp000 events obtained by Brookhaven experiment E852. The expected J{sup PC}=1{sup ++}a{sub 1}(1260) , 2{sup ++}a{sub 2}(1320) , and 2{sup {minus}+}{pi}{sub 2}(1670) resonant states are clearly observed. The exotic J{sup PC}=1{sup {minus}+} wave produced in the natural parity exchange processes shows distinct resonancelike phase motion at about 1.6 GeV/c{sup 2} in the {rho}{pi} channel. A mass-dependent fit results in a resonance mass of 1593{plus_minus}8{sup +29}{sub {minus}47} MeV /c{sup 2} and a width of 168{plus_minus}20{sup +150}{sub {minus}12} MeV /c{sup 2} . {copyright} {ital 1998} {ital The American Physical Society }