119191195
The Majorana Parts Tracking Database
The Majorana Demonstrator is an ultra-low background physics experiment searching for the neutrinoless double beta decay of 76 Ge. The Majorana Parts Tracking Database is used to record the history of components used in the construction of the Demonstrator. The tracking implementation takes a novel approach based on the schema-free database technology CouchDB. Transportation, storage, and processes undergone by parts such as machining or cleaning are linked to part records. Tracking parts provides a great logistics benefit and an important quality a ssurance reference during construction. In addition, the l ocation history of parts provides an estimate of their exposure to cosmic radiation. A web application for data entry and a radiation exposure calculator have been developed as tools for achieving the extreme radio-purity required for this rare decay search.
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.
32025587
High-precision B(E2) measurements of semi-magic 58,60,62,64Ni by Coulomb excitation
J. M. Allmond,1 B. A. Brown,2,3 A. E. Stuchbery,4 A. Galindo-Uribarri,5,6 E. Padilla-Rodal,7 D. C. Radford,5 J. C. Batchelder,8 M. E. Howard,9 J. F. Liang,5 B. Manning,9 R. L. Varner,5 and C.-H. Yu5 1JINPA, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 2National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA 3Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA 4Department of Nuclear Physics, Australian National University, Canberra ACT 0200, Australia 5Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 6Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA 7Instituto de Ciencias Nucleares, UNAM, AP 70-543, 04510 Mexico, D.F., Mexico 8UNIRIB, Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831, USA 9Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903, USA (Received 13 May 2014; revised manuscript received 7 August 2014; published 15 September 2014)
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.
119191195
The Majorana Parts Tracking Database
The Majorana Demonstrator is an ultra-low background physics experiment searching for the neutrinoless double beta decay of 76 Ge. The Majorana Parts Tracking Database is used to record the history of components used in the construction of the Demonstrator. The tracking implementation takes a novel approach based on the schema-free database technology CouchDB. Transportation, storage, and processes undergone by parts such as machining or cleaning are linked to part records. Tracking parts provides a great logistics benefit and an important quality a ssurance reference during construction. In addition, the l ocation history of parts provides an estimate of their exposure to cosmic radiation. A web application for data entry and a radiation exposure calculator have been developed as tools for achieving the extreme radio-purity required for this rare decay search.
119301804
The Majorana Demonstrator: A Search for Neutrinoless Double-beta Decay of 76Ge
Neutrinoless double-beta decay is a hypothesized process where in some even-even nuclei it might be possible for two neutrons to simultaneously decay into two protons and two electrons without emitting neutrinos. This is possible only if neutrinos are Majorana particles, i.e. fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The observation of neutrinoless double-beta decay would also provide complementary information related to neutrino masses. The Majorana Collaboration is constructing the Majorana Demonstrator, a 40-kg modular germanium detector array, to search for the Neutrinoless double-beta decay of 76Ge and to demonstrate a background rate at or below 3 counts/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039 keV Q-value for 76Ge Neutrinoless double-beta decay. In this paper, we discuss the physics of neutrinoless double beta decay and then focus on the Majorana Demonstrator, including its design and approach to achieve ultra-low backgrounds and the status of the experiment.
119291201
Asymmetric left-right model and the top pair forward-backward asymmetry
The forward-backward asymmetry measurement in top-pair production at the Tevatron is about $2\ensuremath{\sigma}$ from the standard model prediction. We propose an asymmetric left-right model, which includes a ${W}^{\ensuremath{'}}$ boson with a right-handed coupling of down to top quark, and a ${Z}^{\ensuremath{'}}$ boson with diagonal couplings to the up, top, and down quarks with ${M}_{{W}^{\ensuremath{'}}}\ensuremath{\approx}175\text{ }\text{ }\mathrm{GeV}$ and ${M}_{{Z}^{\ensuremath{'}}}\ensuremath{\approx}900\text{ }\text{ }\mathrm{GeV}$. The model accounts for the asymmetry while remaining consistent with the top-pair total cross section and invariant mass distribution.
38643705
BEPCII Interaction Region Design and Construction Status
BEPC (Beijing Electron Positron Collider) is now upgrading to a double-ring collider which requires a new storage ring to be built in the existing tunnel. A new and compact interaction region (IR) has been designed to allow a peak luminosity of 1033cm-2s-1from an equal beam energy of 1.89 GeV, a crossing angle, 93 bunches with maximum beam current of 0.91 A . The multi-purpose superconducting magnets and conventional dual aperture quadrupoles are used as final focusing quadrupole in the interaction region. The two beams collide at the interaction point with a crossing angle of ± 11 mrad and further beams separation is enhanced with the help of a septum bending magnet which locates just beyond the superconducting magnet and acts on the outgoing beam lines only. This paper will describe the IR design and the construction status.
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.
119237175
Taking a Razor to Dark Matter Parameter Space at the LHC
Dark matter (DM) has been searched for at colliders in a largely model independent fashion by looking for an excess number of events involving a single jet, or photon, and missing energy. We investigate the possibility of looking for excesses in more inclusive jet channels. Events with multiple jets contain more information and thus more handles to increase the signal to background ratio. In particular, we adapt the recent CMS "razor" analysis from a search for supersymmetry to a search for DM. We consider simplified models where DM is a Dirac fermion that couples to the quarks of the Standard Model (SM) through exchange of vector or axial-vector mediators or to gluons through scalar exchange. We consider both light and heavy (leading to effective contact interactions) mediators. Since the razor analysis requires multiple jets in the final state, the data set is complementary to that used for the monojet search and thus the bounds can be combined.
121335136
Design and field measurement of the BEPC-II interaction region dual-aperture quadrupoles
With the Beijing Electron Positron Collider upgrade project (BEPC-II), two dual-aperture septum-style quadrupole magnets are used in the interaction region for the final focusing of the electron and positron beams. The BEPC-II lattice design calls for the same high quality integral quadrupole field and large good field region in both apertures for each magnet. Two-dimensional contour optimization and pole-end chamfer iteration are used to minimize the systematic harmonic errors. Unexpected non-systematic errors induced by the unsymmetrical structure and the manufacturing errors are compensated with the pole-end shimming. Magnet measurements with rotating coils are performed to guide and confirm the magnet design. This paper discusses the design consideration, optimizing procedure and measurement results of these dual-aperture magnets.