122503839
Properties of an Accelerating Gauss-Bonnet Vacuum in Five Dimensions
The causal structure of a five-dimensional C-metric like vacuum solution of Gauss-Bonnet gravity is analyzed in detail, the Gauss-Bonnet parameter make it more complex than that of a C-metric like solution of Einstein gravity. The acceleration of the observer fixed at a spatial position is calculated, the effect of the Gauss-Bonnet parameter comes in, but the acceleration of the origin is not affected by the parameter. The geodesics of the test particles in the spacetime are investigated, it is found that objects accelerate to go to the horizon in the accelerating spacetime.
53453694
Extended phase space thermodynamics for third-order Lovelock black holes in diverse dimensions
Treating the cosmological constant as thermodynamic pressure and its conjugate as thermodynamic volume, we investigate the critical behavior of the third-order Lovelock black holes in diverse dimensions. For black hole horizons with different normalized sectional curvature $$k=0,\pm 1$$k=0,±1, the corresponding critical behaviors differ drastically. For $$k=0$$k=0, there is no critical point in the extended thermodynamic phase space. For $$k=-1$$k=-1, there is a single critical point in any dimension $$d\ge 7$$d≥7, and for $$k=+1$$k=+1, there is a single critical point in $$7$$7 dimensions and two critical points in 8, 9, 10, 11 dimensions. We studied the corresponding phase structures in all possible cases.
117043294
Three dimensional rotating hairy black holes, asymptotics and thermodynamics
A rotating hairy black hole solution is found in gravity minimally coupled to a self-interacting real scalar field in three spacetime dimensions. Then we discuss analytically the horizon structure and find an analogue of the famous Kerr bound in (2+1) dimensions because of the existence of black hole horizons. We present the asymptotic symmetries and find the same symmetry group (i.e. the conformal group) and central charge as in pure gravity. Based on the asymptotic behavior, the mass and angular momentum are presented by the Regge-Teitelboim approach. Other thermodynamic quantities are also obtained and the first law of black hole thermodynamics and Smarr relation are checked. In addition, we also investigate the local thermodynamic stability and find the existence of Hawking-Page phase transition in the rotating hairy black hole.
17939294
Yang-Type Monopoles In 5 Dimensional Curved Space-Time
Motivated by Gibbons and Townsend's recent work, we construct Yang-Type monopoles in maximally symmetric space-time. We then analyze the dependence of horizon structure of the space-times around the 5-dimensional monopoles on the relative strength of gravitations to Yang-Mills interactions. We also analyze the stability of the monopoles against tensor type perturbations on metrics.
118693623
Angular Reconstruction of a Lead Scintillating-Fiber Sandwiched Electromagnetic Calorimeter
The Neighbor Cell Deposited Energy Ratio (NCDER) is a new method that is proposed to reconstruct incidence position in a single layer for a 3-dimensional imaging electromagnetic calorimeter (ECAL). This method was applied to reconstruct the ECAL test beam data for the Alpha Magnetic Spectrometer-02 (AMS-02). The results show that this method can achieve an angular resolution of 7.36 +/- 0.08 degrees/root E circle plus 0.28 +/- 0.02 degrees in the determination of the photon's direction, which is much more precise than that obtained with the commonly-adopted Center of Gravity (COG) method (8.4 +/- 0.1 degrees/root E circle plus 0.8 +/- 0.3 degrees). Furthermore, since it uses only the properties of electromagnetic showers, this new method could also be used for other type of fine grain sampling calorimeters.
118658801
Note on a noncritical holographic model with a magnetic field
We consider a noncritical holographic model constructed from an intersecting brane configuration D4 root D4-D4 with an external magnetic field. We investigate the influences of this magnetic field on strongly coupled dynamics by the gauge/gravity correspondence.
13286367
Jet quenching parameters of Sakai-Sugimoto Model
Using gauge theory/string duality, we calculated the jet quenching parameter $\hat{q}$ of the Sakai-Sugimoto model in various phases. Being different from the $\mathcal{N}=4$ SYM theory where $\hat{q}\propto T^3$, we find that $\hat{q}\propto T^4/T_d$, where $T_d$ is the critical temperature of the confined/deconfined phase transition. By analyzing the $\hat{q}$ in different phases of this theory, we get better understanding about some statements in previous works, such as the non-universality and the explanation of discrepancies between the theory predictions and experiments.
39060444
NEW HOM COUPLER DESIGN FOR HIGH CURRENT SRF CAVITY
Damping higher order modes (HOMs) significantly to avoid beam instability is a challenge for the high current Energy Recovery Linac-based eRHIC at BNL. To avoid the overheating effect and high tuning sensitivity, current, a new band-stop HOM coupler is being designed at BNL. The new HOM coupler has a bandwidth of tens of MHz to reject the fundamental mode, which will avoid overheating due to fundamental frequency shifting because of cooling down. In addition, the S21 parameter of the band-pass filter is nearly flat from first higher order mode to 5 times the fundamental frequency. The simulation results showed that the new couplers effectively damp HOMs for the eRHIC cavity with enlarged beam tube diameter and 2 120{sup o} HOM couplers at each side of cavity. This paper presents the design of HOM coupler, HOM damping capacity for eRHIC cavity and prototype test results.