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.
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.
119298687
Supersymmetric Custodial Higgs Triplets and the Breaking of Universality
Higgs triplet models are known to have difficulties obtaining agreement with electroweak precision data and in particular constraints on the $\rho$ parameter. Either a global $SU(2)_L \otimes SU(2)_R$ symmetry has to be imposed on the scalar potential at the electroweak scale, as done in the well-known Georgi-Machacek (GM) model, or the triplet vacuum expectation values must be very small. We construct a supersymmetric model that can satisfy constraints on the $\rho$ parameter, even if these two conditions are not fulfilled. We supersymmetrize the GM model by imposing the $SU(2)_L \otimes SU(2)_R$ symmetry at a scale $\mathcal M$, which we argue should be at or above the messenger scale, where supersymmetry breaking is transmitted to the observable sector. We show that scales $\mathcal M$ well above 100 TeV and sizable contributions from the triplets to electroweak symmetry breaking can be comfortably accommodated. We discuss the main phenomenological properties of the model and demonstrate that the departure from custodial symmetry at the electroweak scale, due to radiative breaking, can show up at the LHC as a deviation in the `universal' relation for the Higgs couplings to $WW$ and $ZZ$. As a by-product of supersymmetry, we also show that one can easily obtain both large tree-level \emph{and} one loop corrections to the Higgs mass. This allows for stops that can be significantly lighter and with smaller mixing than those needed in the MSSM.
119191703
Low background signal readout electronics for the Majorana Demonstrator
The Majorana Demonstrator is a planned 40 kg array of Germanium detectors intended to demonstrate the feasibility of constructing a tonne-scale experiment that will seek neutrinoless double beta decay (0νββ) in 76Ge. Such an experiment would require backgrounds of less than 1 count/tonne-year in the 4 keV region of interest around the 2039 keV Q-value of the ββ decay. Designing low-noise electronics, which must be placed in close proximity to the detectors, presents a challenge to reaching this background target. This paper will discuss the Majorana collaboration's solutions to some of these challenges.
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)
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.
118567857
PROPOSAL OF AN INVERSE LOGARITHM SCALING LAW FOR THE LUMINOSITY EVOLUTION
A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. It was showed that dynamic aperture has a logarithmic dependence on time, which would be suggested by some fundamental theorems of the theory of dynamical systems. Such a scaling law was recently extended also to the intensity evolution in a storage ring. In this paper, inspired by these results, and inverse logarithm scaling law for the luminosity in a circular collider is proposed. Such a time-dependence is then tested against the data from the LHC physics runs and also with some examples from other machines. The results are presented and discussed in detail.