124889910
Recent Beijing Spectroscopy (BES) results
AbstractRecent experimental results from Beijing Spectroscopy (BES) are reviewed, including the hadron spectroscopy from J/ψ decays, and a number of new states are found or confirmed, including σ, κ, X(1835), ωφ threshold enhancement in J/ψ→γωφ, a broad resonance in J/ψ→K+K−π0, decay studies of ψ(2S) and χCJ, as well as the results of ψ(3770) non-D$$
\bar D
$$ decays. The current status of BEPCII/BESIII, the major upgrade of BEPC/BESII, is also reported.
118997767
Forward Charge Flow in Hadronic J/psi Production
109503889
EM Calorimeter in BESIII Experiment
BESIII EM Calorimeter (EMC) is based on CsI crystals, working at upgraded Beijing Electron Positron Collider (BEPC), called BEPCII. The overall BEPCII and BESIII design and current status are briefly described. The design and construction of EMC and its performance are presented. EMC works very well and its performances reach the design expectations, it plays an important roll in detector operation and in the BESIII trigger. There are some special features in the EMC construction and reconstruction: the crystals are assembled without support wall to reduce dead area; the time information of the EM clusters can help to suppress the machine background; the detector noise is smaller than similar detectors; the energy reconstruction with TOF signals helps to improve the energy resolution, especially for low energy showers. Several physics papers mainly based on EMC information have been published.
123211493
Exploring the feasibility of a separated function RFQ with mini-vane structure
The accelerating field in the conventional RFQ is originated by the surface modulation of the quadruple electrodes. However, the axial accelerating field generated in this way is quite limited. To enhance the energy gain as well as the focusing power, a post-RFQ accelerating structure called separated function RFQ (SFRFQ) was proposed (Progr. Nat. Sci. 12(1) (2002) 23), and its feasibility has been explored (Chin. Phys. 51(6) (2002)). The RF accelerating field in the SFRFQ structure mainly occurs at gaps between periodical cells, while the electrical quadruple field inside the cells provides the transverse focusing. It turns out that the overall performance can be improved considerably, comparing with that of conventional RFQ. The preliminary results of calculation and model measurements are presented and discussed in the paper.
179453560
NEW BES AND CLEO RESULTS
118124145
BEPCII/BESIII Upgrade and the Prospective Physics
The Status of BEPCII/BESIII upgrade is described, BEPCII is designed to reach a luminosity of $10^{33}/cm^{-2}s^{-1}$ at c. m. energy of 3.89GeV, and BESIII detector is fully rebuilt. The project is on track and is progressing well. The machine and detector are expected to commission together at the late half of 2007, and start to take some engineer run end of 2007 or beginning of 2008.
118554000
OBSERVATION OF A RIDGE CORRELATION STRUCTURE IN HIGH MULTIPLICITY PROTON–PROTON COLLISIONS: A BRIEF REVIEW
This paper briefly reviews the striking experimental observation of a ridge-like dihadron correlation structure in high multiplicity proton–proton collisions at the Large Hadron Collider (LHC). Recent progress of both experimental and theoretical efforts on understanding the physical origin of the novel effect is reviewed. Outlook on future direction of possible new studies is discussed.
118424125
CP asymmetry in $B\to \phi K_S$ in a SUSY SO(10) GUT
We study the $B\to \phi K_S$ decay in a SUSY SO(10) GUT. We calculate the mass spectrum of sparticles for a given set of parameters at the GUT scale. We complete the calculations of the Wilson coefficients of operators including the new operators which are induced by NHB penguins at LO using the MIA with double insertions. It is shown that the recent experimental results on the time-dependent CP asymmetry $S_{\phi K}$ in $B\to \phi K_S$, which is negative and can not be explained in SM, can be explained in the model where there are flavor non-diagonal right-handed down squark mass matrix elements of 2nd and 3rd generations whose size satisfies all relevant constraints from known experiments ($\tau \to \mu \gamma$, $B\to X_S\gamma, B_s\to \mu^+\mu^-, B\to X_s \mu^+\mu^-, B\to X_s g, \Delta M_s$, etc.). At the same time, the branching ratio for the decay can also be in agreement with experimental measurements.
16608072
SDSS J124602.54+011318.8: A Highly Variable AGN, Not an Orphan GRB Afterglow
The optically variable source SDSS J124602.54+011318.8 first appears in Sloan Digital Sky Survey (SDSS) data as a bright point source with nonstellar colors. Subsequent SDSS imaging and spectroscopy showed that the point source declined or disappeared, revealing an underlying host galaxy at z = 0.385. Based on these properties, the source was suggested to be a candidate “orphan afterglow”: a moderately beamed optical transient, associated with a gamma-ray burst (GRB) whose highly beamed radiation cone does not include our line of sight. We present new imaging and spectroscopic observations of this source. When combined with a careful re-analysis of archival optical and radio data, the observations prove that SDSS J124602.54+011318.8 is in fact an unusual radioloud AGN, probably in the BL Lac class. The object displays strong photometric variability on time scales of weeks to years, including several bright flares, similar to the one initially reported. The SDSS observations are therefore almost certainly not related to a GRB. The optical spectrum of this object dramatically changes in correlation with its optical brightness. At the bright phase, weak, narrow oxygen emission lines and probably a broader Hα line are superposed on a blue continuum. As the flux decreases, the spectrum becomes dominated by the host galaxy light, with emerging stellar absorption lines. The narrow and broad emission lines persist. We briefly discuss the implications of this discovery on the study of AGNs and other optically variable or transient phenomena. Subject headings: galaxies: active, BL Lacertae objects: general, gamma rays: bursts
119292700
Matter fields near quantum critical point in (2+1)-dimensional U(1) gauge theory
We study chiral phase transition and confinement of matter fields in (2+1)-dimensional U(1) gauge theory of massless Dirac fermions and scalar bosons. The vanishing scalar boson mass, r = 0, defines a quantum critical point between the Higgs phase and the Coulomb phase. We consider only the critical point r = 0 and the Coulomb phase with r > 0. The Dirac fermion acquires a dynamical mass when its flavor is less than certain critical value N c f , which depends quantitatively on the flavor Nb and the scalar boson mass r. When Nf < N c f , the matter fields carrying internal gauge charge are all confined if r 6 0 but are deconfined at the quantum critical point r = 0. The system has distinct low-energy elementary excitations at the critical point r = 0 and in the Coulomb phase with r 6 0. We calculate the specific heat and susceptibility of the system at r = 0 and r 6 0, which can help to detect the quantum critical point and to judge whether dynamical fermion mass generation takes place.
9048620
On string theory duals of Lifshitz-like fixed points
We present type IIB supergravity solutions which are expected to be dual to certain Lifshitz-like fixed points with anisotropic scale invariance. They are expected to describe a class of D3-D7 systems and their finite temperature generalizations are straightforward. We show that there exist solutions that interpolate between these anisotropic solutions in the IR and the standard AdS5 solutions in the UV. This predicts anisotropic RG flows from familiar isotropic fixed points to anisotropic ones. In our case, these RG flows are triggered by a non-zero theta-angle in Yang-Mills theories that linearly depends on one of the spatial coordinates. We study the perturbations around these backgrounds and discuss the possibility of instability. We also holographically compute their thermal entropies, viscosities, and entanglement entropies.