119248652
MAJORANA Collaboration's Experience with Germanium Detectors
The goal of the \textsc{Majorana} \textsc{Demonstrator} project is to search for 0$\nu\beta\beta$ decay in $^{76}\mathrm{Ge}$. Of all candidate isotopes for 0$\nu\beta\beta$, $^{76}\mathrm{Ge}$ has some of the most favorable characteristics. Germanium detectors are a well established technology, and in searches for 0$\nu\beta\beta$, the high purity germanium crystal acts simultaneously as source and detector. Furthermore, p-type germanium detectors provide excellent energy resolution and a specially designed point contact geometry allows for sensitive pulse shape discrimination. This paper will summarize the experiences the \textsc{Majorana} collaboration made with enriched germanium detectors manufactured by ORTEC$^{\circledR}$. The process from production, to characterization and integration in \textsc{Majorana} mounting structure will be described. A summary of the performance of all enriched germanium detectors will be given.
118542562
Status of the MAJORANA DEMONSTRATOR
The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, modular, HPGe detector array with a mass of 44-kg (29 kg 76Ge and 15 kg natGe) to search for neutrinoless double beta decay in Ge-76. The next generation of tonne-scale Ge-based neutrinoless double beta decay searches will probe the neutrino mass scale in the inverted-hierarchy region. The MAJORANA DEMONSTRATOR is envisioned to demonstrate a path forward to achieve a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value of 2039 keV. The MAJORANA DEMONSTRATOR follows a modular implementation to be easily scalable to the next generation experiment. First, the prototype module was assembled; it has been continuously taking data from July 2014 to June 2015. Second, Module 1 with more than half of the total enriched detectors and some natural detectors has been assembled and it is being commissioned. Finally, the assembly of Module 2, which will complete MAJORANA DEMONSTRATOR, is already in progress.
119013150
Looking for parity nonconservation from strong interactions beyond QCD
Quantum Chromodynamics (QCD), the gauge eld theory describing the strong interactions of colored quarks and gluons in the Standard Model 12 , has been extraordinarily successful in describing physics in both non-perturbative and perturbative regimes. Using the positivity of the Euclidean path integrand for Yang-Mills theory, Vafa and Witten proved that QCD does not spontaneously break parity or CP if = 0 3 . CP conservation in the strong interactions is necessitated by the extreme smallness of experimental upper bounds on the neutron electric dipole moment a . It has been suggested that heavy ion collisions may form metastable phases which allow for parity nonconservation 5 . An induced charge separation along the angular momentum vector of the collision would create an electric dipole moment of the hot gluon matter. There are ongoing searches by the STAR collaboration 6 at the Relativistic Heavy Ion Collider (RHIC) to establish such an eect. Also, parityviolating eects can be induced by topological solutions in QCD.
123625266
Interaction region design and realization for the Beijing Electron Positron Collider
The Beijing Electron Positron Collider (BEPC) has been upgraded as a double-ring factory-like collider (BEPCII). A compact interaction region (IR), which is the most complicated region in the BEPCII, has been designed to afford a peak luminosity of 1 x 10(33) cm(-2) s(-1) with an equal beam energy of 1.89 GeV, a cross angle of +/-11 mrad, 93 bunches and maximum beam current of 0.91 A. All the components of the IR have been fabricated successfully. The design and realization of the interaction region for the BEPCII will be introduced in detail. (C) 2009 Elsevier B.V. All rights reserved.
119205976
Tevatron Asymmetry of Tops in a W, Z Model
Recent results from the CDF Collaboration indicate that the top-pair forward-backward asymmetry is largest in regions of high rapidity dierence j yj and invariant mass Mt t: We show that experimental observations can be explained by our previously proposed Asymmetric Left-Right Model (ALRM). The gauge symmetry U 0 (1) SU 0 (2) SU(2) is broken by a triplet Higgs in the primed sector. The W 0 boson has a (t;d) right-handed coupling and the Z 0 boson has diagonal fermion couplings. We determine the model parameters to be MW0 = 700 GeV, MZ0 = 1 TeV, and charged current coupling g 0 = 3. The W 0 and Z 0 total decay widths are ofO(100 GeV). The signals from Z 0 ! t t and W 0 ! tb at the LHC will test the model.