119109044
High-energy high-luminosity electron-ion collider eRHIC
Joanne Beebe-Wang, Sergey Belomestnykh, Michael M. Blaskiewicz, Rama Calaga, XiangyunChang, Alexei Fedotov, David Gassner, Harald Hahn, Ping He, William Jackson, Animesh Jain,Elliott C.Johnson, Dmitry Kayran, Jorg Kewisch, Yun Luo, George Mahler, Gary McIntyre, WuzhengMeng, Michiko Minty, Brett Parker, Alexander Pikin, Vadim Ptitsyn, Triveni Rao, Thomas Roser, JohnSkaritka, Brian Sheehy, Steven Tepikian, Yatming Than, Dejan Trbojevic, Nicholaos Tsoupas, JosephTuozzolo, Gang Wang, Qiong Wu, Wencan Xu, and Anatoly Zelenski
107681863
Development of fundamental power coupler for high-current superconducting RF cavity
Brookhaven National Laboratory took a project of developing a 704 MHz five-cell superconducting RF cavity for high-current linacs, including Energy Recovery Linac (ERL) for planned electron-hadron collider eRHIC. The cavity will be fed by a high-power RF amplifier using a coaxial Fundamental Power Coupler (FPC), which delivers 20 kW of CW RF power to the cavity. The design of FPC is one of the important aspects as one has to take into account the heat losses dissipated on the surface of the conductor by RF fields along with that of the static heat load. Using a simple simulation model we show the temperature profile and the heat load dissipated along the coupler length. To minimize the heat load on FPC near the cavity end, a thermal intercept is required at an appropriate location on FPC. A 10 K intercept was chosen and its location optimized with our simulation code. The requirement on the helium gas flow rate for the effective heat removal from the thermal intercept is also discussed.
55660748
HOM identification by bead pulling in the Brookhaven ERL cavity
Abstract Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q -factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q ≥10 6 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S 21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the results for HOMs in the first two dipole bands, the un-damped modes in the first quadrupole band, and the identification of several high- Q modes beyond.
164766924
The status of the BNL \& ER
124762878
Results of R&D on a new construction technique for W/ScFi Calorimeters
We report on results of an R&D program to develop new, simple and cost effective techniques to build compact sampling calorimeters utilizing tungsten powder and scintillating fibers. Such calorimeter detectors are under consideration for experiments at the planned Electron Ion Collider and the future upgrade of the STAR experiment at RHIC (BNL). In the first year of this R&D project we built two prototypes of very compact electromagnetic calorimeters and tested them at FNAL test beam T1018 in January 2012. Details of the construction technique, results of the test run and future plan will be presented.
120755700
The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment
The MAJORANA DEMONSTRATOR will search for the neutrinoless double-beta decay of the isotope Ge with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. The DEMONSTRATOR is being assembled at the 4850-foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the DEMONSTRATOR and the details of its design.
119069530
Landau meets Newton: time translation symmetry breaking in classical mechanics
AbstractEvery classical Newtonian mechanical system can be equipped with anonstandard Hamiltonian structure, in which the Hamiltonian is the squareof the canonical Hamiltonian up to a constant shift, and the Poisson bracketis nonlinear. In such a formalism, time translation symmetry can be spon-taneously broken, provided the potential function becomes negative. A niceanalogy between time translation symmetry breaking and the Landau the-ory of second order phase transitions is established, together with severalexample cases illustrating time translation breaking ground states. In par-ticular, the CDM model of FRW cosmology is reformulated as the timetranslation symmetry breaking ground states.Keywords: time translation symmetry breaking, Hamiltonian formalism,Landau theory of phase transition, CDM modelPACS: 1 Introduction Spontaneous symmetry breaking plays an essential role in many areas in moderntheoretical physics such as the gauge theory of particle physics and the Landau-Ginzberg theory of phase transitions in condensed matter physics. Spontaneouslybroken symmetries can either be internal symmetry (such as gauge and chiralsymmetries) or spacial symmetry (such as space translation and rotation symme-tries). Shapere and Wilczek recently discovered [1] that even the time translationsymmetry can be spontaneously broken in some singular Lagrangian systems. Ina previous work [2], we showed that the spontaneous breaking of time transla-tion symmetry can also be described in Hamiltonian formalism using some non-1
119294975
The entropy sum of (A)dS black holes in four and higher dimensions
We present the "entropy sum" relation of (A)dS charged black holes in higher-dimensional Einstein-Maxwell gravity, f(R) gravity, Gauss-Bonnet gravity and gauged supergravity. For their "entropy sum" with the necessary effect of the unphysical "virtual" horizon included, we conclude the general results that the cosmological constant dependence and Gauss-Bonnet coupling constant dependence do hold in both the four and six dimensions, while the "entropy sum" is always vanishing in odd dimensions. Furthermore, the "entropy sum" of all horizons is related to the geometry of the horizons in four and six dimensions. In these explicitly four cases, one also finds that the conserved charges M (the mass), Q (the charge from Maxwell field or supergravity) and the parameter a (the angular momentum) play no role in the "entropy sum" relations.
118838150
Recent Heavy Flavor Results at RHIC
We summarize the recent experimental results of heavy favor physics from the Relativistic Heavy Ion Collider (RHIC) in Brookhaven National Lab (BNL) at Long Island, New York, USA.We will discuss the directly reconstructed open charm mesons as well as electrons from heavy favor hadron decays. The charm and bottom quark production cross-sections have also been measured. We will also discuss JPsi and Upsilon states in p+p and heavy ion collisions. The studies described here were carried out and reported by the STAR and PHENIX collaborations at RHIC.