The ALICE forward muon spectrometer

The physics capabilitites of the ALICE forward muon spectrometer are reviewed.     

Electroweak boson detection in the ALICE muon spectrometer

The ALICE capabilities for W and Z detection at LHC are discussed. The contributions to single muon transverse momentum distribution are evaluated. The expected performance of the muon spectrometer for detecting W and Z bosons via their muonic decay is presented. Possible application for the study of in-medium effects in ultrarelativistic heavy ion collisions is discussed.     

Proton-proton physics with the ALICE muon spectrometer at the LHC

ALICE, the dedicated heavy-ion experiment at the LHC, has also an important proton-proton physics program. The ALICE muon spectrometer will be presented and the corresponding physics analysis will be reviewed. A particular emphasis will be placed on heavy-flavor measurement. (for the ALICE Collaboration) The text was submitted by the author in English.     

A fast muon trigger for the PHENIX forward spectrometer upgrade

The PHENIX forward upgrade adds nosecone calorimeters and level-1 trigger (LVL-1) detectors to the muon forward spectrometers. The muon detector will trigger on high pT muons from W decay and reject background. This will enable study of quark and anti-quark polarizations in the proton. The upgrade will add momentum and timing information to the present muon trigger. Signals from 3 Resistive Plate Chambers (RPCs) will provide momentum and timing information for the LVL-1 trigger. Each RPC carries a plane with coarse structure to establish a space point for timing and one with radial cathode strips for azimuthal resolution. Timing resolution of ≈ 2 ns rejects beam-related backgrounds and tracking from RPCs minimizes muons from hadron decays. RPC information is sent by optical. bers to LVL-1 trigger processors. A discussion of physics measurements possible, layout of the upgrade and details of RPC design and tests are given below. for the PHENIX collaboration Presented in the Poster Session “Future Experiments and Facilities” at the 18th International Conference “Quark Matter 2005”, Budapest, Hungary, 4–9 August 2005.     

Study of the quarkonium polarization in the muon channel at ALICE

The study of quarkonium polarization at hadron colliders represents an important test of the production models. Recent results, obtained at CDF, are in striking disagreement with NRQCD predictions, although such a model correctly reproduces the production cross sections. Furthermore, in nucleus-nucleus collisions, the observed degree of polarization may be related to the characteristics of deconfined matter. Because of these interesting features, quarkonium polarization will surely represent an interesting observable at LHC energies. In ALICE, the polarization of the Ω and Γ states can be measured in the dilepton channel, both in the central barrel and in the forward (2.5<y<4) muon arm. We present the results of a feasibility study, relative to the muon channel, concerning p-p and Pb-Pb collisions, showing the expected performance for the measurement of J/Ω and Γ polarization, both as a function of transverse momentum and centrality.     

A new spectrometer for muon spin rotation

We report on the development of a spectrometer for Muon Spin Rotation based on multiwire proportional chambers. The coordinates provided by telescopes each composed of two chambers are used to reconstruct the muon and the positron trajectories in ⁺ e⁺+v_e+ decay. A real-time analysis program verifies that the two tracks intersect within the target: this constitutes a very stringent test to veto events which do not correspond to a muon decay. The results of some experiments are given in order to illustrate the field of application of this spectrometer.     

Prospects for strangeness measurement in ALICE

The study of strangeness production at LHC will bring significant information on the bulk chemical properties, its dynamics, and the hadronization mechanisms involved at these energies. The ALICE experiment will measure strange particles from topology (secondary vertices) and from resonance decays over a wide range in transverse momentum and shed light on this new QCD regime. These motivations will be presented as well as the identification performance of ALICE for strange hadrons. (for the ALICE Collaboration) The text was submitted by the author in English.     

Study of the photon identification efficiency with ALICE photon spectrometer

The efficiency for the detection and identification of photons with the ALICE PHOton Spectrometer PHOS has been studied with the Monte-Carlo generated data. In particular, the influence on the efficiency of the PHOS-module edge-effect and of the material in front of PHOS have been examined.     

Study of the photon identification efficiency with ALICE photon spectrometer

The efficiency for the detection and identification of photons with the ALICE PHOton Spectrometer PHOS has been studied with the Monte-Carlo generated data. In particular, the influence on the efficiency of the PHOS-module edge-effect and of the material in front of PHOS have been examined.     

A new forward spectrometer for PHENIX

In the last decade PHENIX has accessed via longitudinal double spin asymmetries the gluon helicity inside the proton, started probing flavor dependent valence and sea quark helicity distributions and started to explore the proton transverse spin structure. A major upgrade is planned for the next decade that will provide an increased acceptance and additional tracking and electromagnetic plus hadronic calorimetry in the forward region. Here, the layout of the new forward detector system will be discussed, together with the new insights in the proton spin structure that the new forward PHENIX spectrometer will provide.     

Magnetic field calculation of the NA4 muon spectrometer

Conclusions The calculations of magnetic field in the NA4 spectrometer provided the magnetic field map for the reconstruction program. The field in iron is toroidal and decreases approximately logarithmically from 2·11 T at the inner edge to 1·77 T at the outer edge. The support of the magnet introduces a small disturbance at a level of 2% in the lower part of the magnet. A flow of the field through the support introduces a normal component of field in a narrow sector around the support leg. The multipole field in the hole has been neglected in the reconstruction program presently used.Dedicated to the 25th anniversary of the Joint Institute for Nuclear Research.On leave of absence fromInstitute of Physics, Czechosl. Acad. Sci., Prague, Czechoslovakia.     

Development of 500 MHz muon spin resonance spectrometer

The 500 MHz muon resonance was newly developed. The system was constructed with 500MHz resonance cavity, pulsed high power RF-source and the superconducting helmholz coil. This system provide the oppotunity to achieve the diamagnetic muon spectroscopy at 37KG and 500MHz. Also muonic radical resonance and muonium resonance at magnetic field corresponding to the 500MHz resonance frequency. Some preliminary but important result was also reported.     

Study of the ALICE performance for the measurement of beauty via the electron decay channel

We present a strategy for the detection of electrons coming from the semi-electronic decay of beauty particles generated in Pb–Pb and p–p collisions at LHC using the ALICE detector. The experiment’s performance for this measurement is evaluated in terms of accessible p_t range and expected uncertainties. PACS 25.75.-q, 12.38.Mh, 13.20.He     

Alignment and measurement of the magnetic field for the BESIII muon counter

Based on cosmic ray events without a magnetic field taken with the BESIII detector during the summer shutdown of BEPCII in 2012 and di-muon events from a data sample taken at center-of-mass energy of 3.686 GeV in 2009, we compare the coordinates of hits registered in the BESIII muon counter with the expected interaction point extrapolated from reconstructed tracks from the inner tracking system in the absence of a magnetic field. By minimizing the difference, we align the muon counter with the inner tracking system. Moreover, the strength of the magnetic field in the muon counter is measured for the first time with di-muon events from data taken at a center-of-mass energy of 3.686 GeV. After the alignment and the magnetic field strength measurement, the offsets in the reconstructed hit positions for muon tracks are reduced, which improves the muon identification. The alignment and magnetic field strength measurement have been adopted in the latest version of the BESIII offline software system. This addition to the software reduces the systematic uncertainty for the physics analysis in cases where the muon counter information is used.     

Precise measurement of the positive muon anomalous magnetic moment

A precise measurement of the anomalous g value, a(mu) = (g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron. The result a(mu+) = 11 659 202(14) (6) x 10(-10) (1.3 ppm) is in good agreement with previous measurements and has an error one third that of the combined previous data. The current theoretical value from the standard model is a(mu)(SM) = 11 659 159.6(6.7) x 10(-10) (0.57 ppm) and a(mu)(exp) - a(mu)(SM) = 43(16) x 10(-10) in which a(mu)(exp) is the world average experimental value.     

Pion exchange and the H1 forward spectrometer data

We point out that the component of the nucleon wave function is vital to the interpretation of the recent H1 data for leading baryon production. While the n/p ratio is equal to two with the component alone, the inclusion of the component brings this ratio very near to unity, as observed in the experiment. This result demonstrates that pion exchange can not only account for leading neutron but also for a large fraction of the leading proton production. Received: 4 December 1998 / Revised version: 1 February 1999 / Published online: 27 April 1999     

星载成像光谱仪杂散光检测技术

介绍了星载成像光谱仪杂散光检测技术在国内外的发展状况,阐述了成像光谱仪杂散光的定义、来源和危害,分析了杂散光检测的必要性。通过截止滤光片法、光谱法、谱杂散光系数法、级数透过率法、氧气吸收光谱及参数拟合法、卷积计算法和矩阵修正法等7种光谱仪器杂散光检测方法优缺点的对比,给出了星载成像光谱仪杂散光检测技术的具体要求和发展趋势,认为单一的检测技术很难满足工程研制的实际需要,针对各研制阶段的组合检测技术将是星载成像光谱仪杂光检测的发展方向。     

MARTA: a high-energy cosmic-ray detector concept for high-accuracy muon measurement

A new concept for the direct measurement of muons in air showers is presented. The concept is based on resistive plate chambers (RPCs), which can directly measure muons with very good space and time resolution. The muon detector is shielded by placing it under another detector able to absorb and measure the electromagnetic component of the showers such as a water-Cherenkov detector, commonly used in air shower arrays. The combination of the two detectors in a single, compact detector unit provides a unique measurement that opens rich possibilities in the study of air showers.