124197197
Structure functions in tau ---> 3 pi neutrino decay
121082248
Prospects of B/c mesons at the Compact Muon Solenoid
The results of two Monte Carlo generators for production of Bc mesons in pp collisions are compared at the large hadron collider energy (s)1/2 = 14 TeV. In the study, the produced Bc mesons were forced to decay into the final states Bslν, Bsπ, J/ψlν, and J/ψπ. We have estimated that about 104 decays of Bc are expected to be recorded during the first year of the CMS running with a lepton trigger. Many Bc studies can be carried out by using these events with a statistical error at the level of 10−2.
123396645
Calibration and performance of the AMS-02 time of flight detector in space
AMS-02 is a high energy particle detector deployed in May 19, 2011 on board of the International Space Station (ISS) where it is expected to be in operation for the ISS lifetime of at least a decade. The main goal of AMS-02 is the detection of cosmic rays and gammas from the GeV to the TeV energy region to search for anti-matter, dark matter and understanding the origin of the cosmic rays. The AMS-02 time of flight (TOF) detector provides the trigger to experiment and allows precise measurements of the cosmic rays velocity and charge magnitude from hydrogen to iron and above. With the data set acquired during the first two and a half years of operation in space, a precise time-dependent calibration for time, velocity and charge measured by the TOF had been developed. The TOF calibration methods are described and the AMS-02 TOF performance in space is presented. (C) 2014 Elsevier B.V. All rights reserved.
209930395
Extraction of the structure functions in tau -> 3 pi nu decay using Li model
The structure functions in the tau --> 3 pi nu decay are extracted using the model proposed by Li. The predictions of Li model are compared with KS ones and the data from OPAL experiment. It is found that predictions by the model for w(A)(Q(2)) are consistent with the data except for in the high energy region (Q(2) > 1.2 GeV2), and w(C), w(D), w(E) normalized to w(A) are in reasonable agreement with the experimental results. Correction factors to the Breit-Wigner distribution of a(1) and the Lagrangian of this decay are proposed to the model.
120081744
Study on The Property of tau Hadronic Decays
119474898
The topological branching fractions of $\tau$ decay at LEP
The paper has heen withdrawn.
168586219
The Network Security Protection System at IHEP-Net
62209352
Volunteer Clouds and Citizen Cyberscience for LHC Physics
Computing for the LHC, and for HEP more generally, is traditionally viewed as requiring specialized infrastructure and software environments, and therefore not compatible with the recent trend in volunteer computing, where volunteers supply free processing time on ordinary PCs and laptops via standard Internet connections. In this paper, we demonstrate that with the use of virtual machine technology, at least some standard LHC computing tasks can be tackled with volunteer computing resources. Specifically, by presenting volunteer computing resources to HEP scientists as a volunteer cloud, essentially identical to a Grid or dedicated cluster from a job submission perspective, LHC simulations can be processed effectively. This article outlines both the technical steps required for such a solution and the implications for LHC computing as well as for LHC public outreach and for participation by scientists from developing regions in LHC research.
118388381
Heavy quarkonium production through the top quark decays via flavor changing neutral currents
The production of the heavy charmonium and $(c\bar{b})$-quarkonium, through the top quark semi-exclusive decays via the flavor changing neutral currents (FCNC), has been systematically studied within the non-relativistic QCD. In different to the conventional squared amplitude approach, to simplify the results as much as possible, we adopt the `improved trace technology' to do our calculation, which deals with the hard scattering directly at the amplitude level. If assuming the higher excited heavy-quarkonium states, such as the color-singlet and spin-triplet $S$-wave state $|[^3S_1]_{\bf 1}\rangle$, the color-singlet $P$-wave states $|[^1P_1]_{\bf 1}\rangle$ and $|[^3P_J]_{\bf 1}\rangle$ (with $J=0,1,2$), and the two color-octet components $|[^1S_0]_{\bf 8}g\rangle$ and $|[^3S_1]_{\bf 8}g\rangle$, decay to the ground color-singlet and spin-singlet $S$-wave state $|[^1S_0]_{\bf 1}\rangle$ with 100% efficiency via the electromagnetic or hadronic radiations, we obtain the total decay width: $\Gamma_{t\to |(c\bar{c})[^1S_0]_{\bf 1}\rangle} = 171.1^{+147.7}_{-68.8}$ KeV and $\Gamma_{t\to |(c\bar{b})[^1S_0]_{\bf 1}\rangle} =7.32^{+2.49}_{-1.75}$ KeV, where the uncertainties are caused by varying $m_t=172.0\pm4.0$ GeV, $m_b=4.90\pm0.40$ GeV and $m_c=1.50\pm0.25$ GeV. At the LHC with the center-of-mass energy $\sqrt{S}=14$ TeV and a high luminosity ${\cal L}\propto 10^{34}{\rm cm}^{-2}{\rm s}^{-1}$, sizable heavy-quarkonium events can be produced through the top quark decays via FCNC.
118387288
Global flow of glasma in high energy nuclear collisions
Abstract We discuss the energy flow of the classical gluon fields created in collisions of heavy nuclei at collider energies. We show how the Yang–Mills analog of Faradayʼs Law and Gaussʼ Law predicts the initial gluon flux tubes to expand or bend. The resulting transverse and longitudinal structure of the Poynting vector field has a rich phenomenology. Besides the well-known radial and elliptic flow in transverse direction, classical quantum chromodynamics predicts a rapidity-odd transverse flow that tilts the fireball for non-central collisions, and it implies a characteristic flow pattern for collisions of non-symmetric systems A + B . The rapidity-odd transverse flow translates into a directed particle flow v 1 which has been observed at RHIC and LHC. The global flow fields in heavy ion collisions could be a powerful check for the validity of classical Yang–Mills dynamics in high energy collisions.
97662282
Electromagnetic calorimeter for the AMS-02 experiment
The electromagnetic calorimeter (ECAL) of the AMS-02 experiment is a 3-dimensional sampling calorimeter, made of lead and scintillating fibers. The detector allows for a high granularity, with 18 samplings in the longitudinal direction, and 72 sampling in the lateral direction. The ECAL primary goal is to measure the energy of cosmic rays up to few TeV, however, thanks to the fine grained structure, it can also provide the separation of positrons from protons, in the GeV to TeV region. A direct measurement of high energy photons with accurate energy and direction determination can also be provided.