117479018
On the jet-like and ring-like substructure in distributions of produced particles in central heavy-ion collisions at ultra-relativistic energies
122689361
Search for New Phenomena with the Monojet and Missing Transverse Momentum Signature Using the ATLAS Detector in $\sqrt{s}=7$ TeV Proton-Proton Collisions
A search for new phenomena in events featuring a high energy jet and large missing transverse momentum in proton-proton collisions at root s = 7 TeV is presented using a dataset corresponding to an integrated luminosity of 33 pb(-1) recorded with the ATLAS detector at the Large Hadron Collider. The number of observed events is consistent with the Standard Model prediction. This result is interpreted in terms of limits on a model of Large Extra Dimensions. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved.
126297547
Experimental study of hadron inclusive production in J / psi energy region
117751922
Substructural dependence of the multiparticle production in relativistic heavy-ion interactions
17251648
Measurement of the DAΦNE luminosity with the KLOE detector using large angle Bhabha scattering
We describe the method of measuring the integrated luminosity of the e+e- collider DAΦNE, the Frascati φ-factory. The measurement is done with the KLOE detector selecting large angle Bhabha scattering events and normalizing them to the effective cross section. The e+e-→e+e-(γ) cross section is calculated using different event generators which account for the $\mathcal{O}(\alpha)$ radiative initial and final state corrections, and the φ resonance contribution. The accuracy of the measurement is 0.6%, where 0.3% comes from systematic errors related to the event counting and 0.5% from theoretical evaluations of the cross section.
118728331
KLOE measurement of the $\sigma(\pi^+ \pi^- (\gamma))$ cross section and the pi+ pi- contribution to the muon anomaly
109912783
ICARUS 600 ton: A status report
The goal of the ICARUS Project is the installation of a multi-kiloton LAr TPC in the underground Gran Sasso Laboratory. The programme foresees the realization of the detector in a modular way. The first step is the construction of a 600 ton module which is now at an advanced phase. It will be mounted and tested in Pavia in one year and then it will be moved to Gran Sasso for the final operation. The major cryogenic and purification systems and the mechanical components of the detector have been constructed and tested in a 10 m3 prototype. The results of these tests are here summarized.
201630181
THE COUPLING COMPENSATION AND MEASUREMENT IN THE INTERACTION REGION OF BEPCII
The detector solenoid field in the BEPCII interaction region will be compensated by six anti-solenoids, which are located nearby the interaction point. Skew quadrupoles are adopted for the global coupling compensation. The coupling compensation scheme and the method to tune and measure the x-y coupling at the interaction point will be introduced in detail. COUPLING COMPENSATION SCHEME The BESIII detector solenoid has maximum field strength of 1.0T over an effective length of ±1.8m around the interaction point (IP) where the particle motion between the horizontal and vertical planes will be coupled. The lattice functions, the vertical emmittance and the tilt angle of beam are strongly related to the coupling parameters. Therefore, without the dedicated coupling compensation it is impossible to meet higher luminosity. According to the requirements of high energy physics, BEPCII will be operated at the energy range from 1.0GeV to 2.1GeV, so the compensation system should be powerful enough to work perfectly for particles within the momentum range. For this purpose an anti-solenoid system has been designed in the superconducting magnet package to realize the local compensation of x-y coupling effects in the interaction region (IR). This system consists of three anti-solenoids AS1, AS2 and AS3 and a skew quadrupole inside the superconducting cryostat. AS1 locates between the IP and the superconducting quadrupole (SCQ) which acts as the first vertical focusing quadrupole. AS2 and the skew quadrupole overlap SCQ, while AS3 locates after SCQ. They are all dedicated to the compensation of the detector fields along the beam line for both e+ and erings which have the same beam energy. The local compensation layout of BEPCII and wiring schematic diagram are shown in Fig. 1. Figure 1: The local coupling compensation layout of BEPCII and wiring schematic diagram. With this compensation scheme, the integral field ∫Bzds between the IP and SCQ is zero. The longitudinal field over SCQ is nearly zero and the integral field ∫Bzds between SCQ and the first horizontal focusing quadrupole is zero too. As well known the compensation of longitudinal field within SCQ region is a key for higher luminosity. The skew quadrupole which overlaps SCQ can make fine tuning of longitudinal field over the SCQ region instead of the mechanical rotation method. AS2 and AS3, which have their own independent trim circuits to allow fine tuning of the anti-solenoid compensation scheme, are in series with AS1. Fig. 2 shows the distribution of the axial combination magnetic field Bz along the axis of BESIII detector after compensation simulated by OPERA-2D code. Figure 2: The distribution of the axial combination magnetic field along the axis of the BESIII detector. Since the anti-solenoids AS1, AS2, AS3 and the skew quadrupole are the common elements for both e+ and erings, it is necessary to add some independent variables for the coupling adjustment of one ring with the coupling of the other ring unchanged. Due to the limitation of free space, we arrange four skew quadrupoles only for each ring, which are distributed in the interaction region, injection regions and RF region respectively for the further fine tuning of coupling. The horizontal dispersion in those regions is free so that the changes of the vertical dispersion and its slope can be neglected during the coupling adjustment. The global coupling parameter and the beam tile angle at the IP of each ring, which are induced by solenoid field, the beam vertical orbit distortion inside the sextupoles and the parasitic x-y coupling due to machine errors, can be compensated by tuning the strength of the skew quadrupoles and antisolenoids. ________________________________________ *Email: yuch@mail.ihep.ac.cn Proceedings of EPAC 2004, Lucerne, Switzerland
10335512
Antilambda production in Au+Au collisions at 11.7A GeV/c.
We present results for antilambda and antiproton production in Au+Au collisions at 11.7 A GeV/c including spectra and extracted invariant yields for both species in central and peripheral collisions in the rapidity range 1.0<y<1.4. The antilambda yield increases from dN(Lambda;)/dy = 1.2(+0.7+0.2)(-0.6-0.2)x10(-3) in peripheral collisions to 19(+4+3)(-5-2)x10(-3) in central collisions. The direct antiproton yield is deduced from the measured total antiproton spectra to extract the ratio of antilambda-to-direct-antiproton production. The Lambda/p ratio near midrapidity increases from 0.26(+0.19+0.5)(-0.15-0.4) in peripheral collisions to 3.6(+4.7+2.7)(-1.8-1.1) in central collisions, a value larger than current theoretical estimates.
118531296
Suppression of the emittance growth induced by coherent synchrotron radiation in triple-bend achromats*
The coherent synchrotron radiation (CSR) effect in a bending path plays an important role in transverse emittance dilution in high-brightness light sources and linear colliders, where the electron beams are of short bunch length and high peak current. Suppression of the emittance growth induced by CSR is critical to preserve the beam quality and help improve the machine performance. It has been shown that the CSR effect in a double-bend achromat (DBA) can be analyzed with the two-dimensional point-kick analysis method. In this paper, this method is applied to analyze the CSR effect in a triple-bend achromat (TBA) with symmetric layout, which is commonly used in the optics designs of energy recovery linacs (ERLs). A condition of cancelling the CSR linear effect in such a TBA is obtained, and is verified through numerical simulations. It is demonstrated that emittance preservation can be achieved with this condition, and to a large extent, has a high tolerance to the fluctuation of the initial transverse phase space distribution of the beam.
121797308
Simultaneous multiplicity and forward energy characterization of particle spectra in Au + Au collisions at 11.6-A-GeV/c
In this paper Au+Au collisions at 11.6A GeV/c are characterized by two global observables: the energy measured near zero degrees (E{sub ZCAL}) and the total event multiplicity. Particle spectra are measured for different event classes that are defined in a two-dimensional grid of both global observables. For moderately central events ({sigma}/{sigma}{sub int}{lt}12{percent}) the proton dN/dy distributions do not depend on E{sub ZCAL} but only on the event multiplicity. In contrast the shape of the proton transverse spectra shows little dependence on the event multiplicity. The change in the proton dN/dy distributions suggests that different conditions are formed in the collision for different event classes. These event classes are studied for signals of new physics by measuring pion and kaon spectra and yields. In the event classes doubly selected on E{sub ZCAL} and multiplicity there is no indication of any unusual pion or kaon yields, spectra, or K/{pi} ratio even in the events with extreme multiplicity. {copyright} {ital 1999} {ital The American Physical Society}