119415668
Progress in FDC project
FDC is a general-purpose program package for Feynman Diagram Calculation. We outline its achievements and focus on its recent progress, automatic construction of the Lagrangian and deduction of the Feynman rules for super-symmetry model, generation of multi-processes and their event generators in the SM and MSSM, and a few special applications. The FDC-homepage is presented to show the automatic translation of FDC's results into HTTP version. (C) 2004 Elsevier B.V. All rights reserved.
119228404
Discovery potential of new boson W1± in the Minimal Higgsless model at LHC
Abstract In this paper, we demonstrate the LHC discovery potential of new charged vector boson W 1 ± predicted by the Minimal Higgsless model in the process p p → W 1 ± q q ′ → W ± Z 0 q q ′ → l ± l + l − ν q q ′ ( l = e , μ ) by analyzing the generator level events of the signal and backgrounds. The generator for the signal p p → W 1 ± q q ′ → W ± Z 0 q q ′ at tree level is developed with the Minimal Higgsless model and then interfaced with PYTHIA for the parton showers and hadronization. The backgrounds are produced with PYTHIA and ACERMC. We give integrated luminosities required to discover 5σ signal as a function of W 1 ± mass.
43082728
Polarization for prompt J/ψ and ψ(2s) production at the Tevatron and LHC.
With nonrelativistic QCD factorization, we present the first complete next-to-leading order study on the polarization of prompt J/ψ hadroproduction by including feeddown from χ(c)((3)P(J)(1),(3)S(1)(8)) and ψ(2s) which turn out to be very important parts. By using the color-octet long-distance matrix elements obtained from a combined fit of the measurements at the Tevatron and LHC for J/ψ, ψ(2s) and χ(c), the prompt J/ψ polarization predictions are presented, and the results are in agreement with the CDF run I data (except two points), but in conflict with the CDF run II data, while they are close to the ALICE data (inclusive J/ψ). The measurements at the LHC are expected to clarify the situation.
118483137
Production of a heavy quarkonium with a photon or via ISR at Z peak in e+e− collider
Considering the possibility to build an e+e− collider at the energies around Z-boson resonance with a luminosity so high as L ∝ 1034 cm−2 s−1 (even higher) and the abilities of a modern synthesis detector, we systematically calculate the exclusive two body processes of the heavy quarkonium production: e+e− annihilates into a heavy quarkonium and a photon, involving the initial state radiation (i.e. ISR) cases, at the energies around the Z-boson resonance. Since the couplings of Z-boson to quarks contain an axial vector term as well as a vector one, a charmonium such as J/ψ or ηc or hc or χcJ …, or a bottomonium such as ϒ or ηb or hb or χbJ …, associating with a photon, may be produced respectively via Z-boson annihilation. If we call such a collider with so high luminosity and running around the Z-boson resonance as a Z-factory, then our results obtained here indicate that experimental studies of the various heavy quarkona (their ground and excited states) via the two-body processes at a Z-factory have outstanding advantages, especially, the production of the possible states with quantum numbers JPC = 1−− via ISR.
119202012
Bridging light-cone and NRQCD approaches: asymptotic behavior of Bc electromagnetic form factor
This work aims at illustrating that, for a class of leading-twist hard exclusive reactions involving two heavy quarkonia, the light-cone approach, when equipped with the strategy of refactorization of the light-cone distribution amplitude of quarkonium, can be employed to elegantly reproduce the corresponding predictions made in the nonrelativistic QCD (NRQCD) factorization approach, order by order in perturbative expansion. Taking the electromagnetic form factor of the Bc meson at large momentum transfer, Q2, as a concrete example, we compare the results obtained from both NRQCD-based and light-cone-based calculations through the next-to-leading order (NLO) in αs, while at the leading order (LO) in both velocity and 1/Q2 expansion, and explicitly confirm their mutual agreement. As a byproduct, we apply our NLO result to explore certain features about the asymptotic behavior of the heavy-light meson form factor. We also address the major theoretical obstacles that prevent us from establishing an analogous equivalence between these two approaches for the double charmonium production process of phenomenological interest, e+e− → J/ψ + ηc.
123106617
Prospects for a new boson W±1 in the minimal Higgsless model at the LHC
The author list originally given in the above article (Ming-Shui Chen, Jian-Guo Bian, Guo-Ming Chen, Hong-Jian He, Chun-Hua Jiang, Zu-Hao Li, Song Liang, Xiang-Wei Meng, Yong-Hui Qi, Zhi-Cheng Tang, Jun-Quan Tao, Zheng Wang, Jian Wang, Jian Wang, Xian-You Wang, Jian-Xiong Wang, Hong Xiao, Min Yang, Jing-Jing Zang, Bin Zhang, Zhen Zhang and Zhen- Xia Zhang) is incorrect. The correct author list is: Ming-Shui Chen, Jian-Guo Bian, Guo-Ming Chen, Chun-Hua Jiang, Zu-Hao Li, Song Liang, Xiang-Wei Meng, Zhi-Cheng Tang, Jun-Quan Tao, Zheng Wang, Jian Wang, Jian Wang, Xian-You Wang, Jian-Xiong Wang, Hong Xiao, Min Yang, Jing-Jing Zang, Bin Zhang, Zhen Zhang and Zhen-Xia Zhang. Hong-Jian He and Yong-Hui Qi did not take part in the writing of this text and do not bear any responsibility for its contents. Also, reference [4] in the paper should be corrected to: [4] Hong-Jian He et al 2008 Phys. Rev. D 78 031701(R)
119241670
Landau Quantization of Massless Dirac Fermions in Topological Insulator
1 Department of Physics, Tsinghua University, Beijing 100084, China 2 Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 3 Microsoft Research, Station Q, University of California, Santa Barbara, CA 93106, USA 4 Department of Physics, Stanford University, Stanford CA 94305, USA 5 Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany * These authors contributed equally to this work. ¶ To whom correspondence should addressed. Email: xc@mail.tsinghua.edu.cn, xcma@aphy.iphy.ac.cn
32668015
A Method to Calibrate Beam Position Monitor at HLS 200 MeV Linac
In order to improve injection efficiency of HLS 200Mev LINAC, we redesign a new strip line beam position monitor system, which is consisted of a strip line structure and a signal processing system. We decide on an online calibration method based on beam to find out the geometry centre displacement and relative gain offset. Before the BPM testing bench has been prepared, we make a simulation based on the model accounted for all factors influencing signal amplitudes and get the calibrating results. At last, we analyze the nonlinearity effect on the calibration results.
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.
54921013
Design and study of a TCF lattice with negative momentum compaction factor
The feasibility of designing a negative momentum compaction factor (alpha(p) < 0) lattice for a circular e(-)e(+) collider is investigated. The modular method for an alpha(p) < 0 lattice is introduced. As a practical example, an alpha(p) < 0 lattice for a Tau-charm factory (TCF) is proposed and studied. (C) 1999 Elsevier Science B.V. All rights reserved.
16148475
Cosmological Evolution of the Duty Cycle of Quasars
Quasars are powered by accretion onto supermassive black holes, but the problem of the duty cycle related to the episodic activity of the black holes remains one of the major questions of the cosmological evolution of quasars. In this Letter, we obtain quasar duty cycles based on analyses of a large sample composed of 10,979 quasars with redshifts z ≤ 2.1 from the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3). We estimate the masses of the quasar black holes and obtain their mass function (MF) in the present sample. We then get the duty cycle (z) = 10-3 ~ 1 based on Soltan's argument, implying that black holes are undergoing multiple episodic activity. We find that the duty cycle has a strong evolution. By comparison, we show that the evolution of the duty cycle follows the history of the cosmic star formation rate (SFR) density in the universe, providing intriguing evidence of a natural connection between star formation and the triggering of black hole activity. Feedback on star formation from black hole activity is briefly discussed.