86860651
Theoretical constraints on additional Higgs bosons in light of the 126 GeV Higgs
A bstractWe present a sum rule for Higgs fields in general representations under SU(2)L × U(1)Y that follows from the connection between the Higgs couplings and the mechanism that gives the electroweak bosons their masses, and at the same time restricts these couplings. Sum rules that follow from perturbative unitarity will require us to include singly and doubly charged Higgses in our analysis. We examine the consequences of these sum rules for Higgs phenomenology in both model independent and model specific ways. The relation between our sum rules and other works, based on dispersion relations, is also clarified.
56563443
On Limit Cycles in Supersymmetric Theories
Abstract Contrary to popular belief conformality does not require zero beta functions. This follows from the work of Jack and Osborn, and examples in non-supersymmetric theories were recently found by some of us. In this Letter we show that such examples are absent in unitary N = 1 supersymmetric four-dimensional field theories. More specifically, we show to all orders in perturbation theory that the beta-function vector field of such theories does not admit limit cycles. A corollary of our result is that unitary N = 1 supersymmetric four-dimensional theories cannot be superscale-invariant without being superconformal.
110445102
Operating a production pilot factory serving several scientific domains
Pilot infrastructures are becoming prominent players in the Grid environment. One of the major advantages is represented by the reduced effort required by the user communities (also known as Virtual Organizations or VOs) due to the outsourcing of the Grid interfacing services, i.e. the pilot factory, to Grid experts. One such pilot factory, based on the glideinWMS pilot infrastructure, is being operated by the Open Science Grid at University of California San Diego (UCSD). This pilot factory is serving multiple VOs from several scientific domains. Currently the three major clients are the analysis operations of the HEP experiment CMS, the community VO HCC, which serves mostly math, biology and computer science users, and the structural biology VO NEBioGrid. The UCSD glidein factory allows the served VOs to use Grid resources distributed over 150 sites in North and South America, in Europe, and in Asia. This paper presents the steps taken to create a production quality pilot factory, together with the challenges encountered along the road.
2024174
Bottom-quark forward-backward asymmetry in the standard model and beyond.
We computed the bottom-quark forward-backward asymmetry at the Tevatron in the standard model (SM) and for several new physics scenarios. Near the Z pole, the SM bottom asymmetry is dominated by tree level exchanges of electroweak gauge bosons. While above the Z pole, next-to-leading order QCD dominates the SM asymmetry as was the case with the top-quark forward-backward asymmetry. Light new physics, M(NP)≲150  GeV, can cause significant deviations from the SM prediction for the bottom asymmetry. The bottom asymmetry can be used to distinguish between competing new physics (NP) explanations of the top asymmetry based on how the NP interferes with s-channel gluon and Z exchange.
89614484
Searching for new physics in the three-body decays of the Higgs-like particle
A bstractWe show that the three-body decays of the resonance recently discovered at the LHC are potentially sensitive to effects of new physics. Even if the fully integrated partial decay widths are consistent with the minimal Standard Model there is information that is lost upon integration, which can be uncovered in the differential decay widths. Concentrating on the decay h → Zℓ$ \overline{\ell} $, we identify the regions in the three-body phase space in which these effects become especially pronounced and could be detected in future experiments.
117827083
Modification to footprint to accommodate an external fixed-target hall
Based on a note from C.T. Murphy on SSC Crystal Extracted Beams, we propose a modification to the footprint for the East Campus to accommodate an external beam area for 20-TeV protons. Because Murphy`s analysis uses a somewhat out-of-date ring configuration, it had to be modified to fit the current machine parameters. However, the same principles were applied. (The revised Murphy note of 9/16/89 uses the current machine parameters and is consistent with this memo.) Basically, to avoid sitting in the halo of the hewn from IR6 and IR7, the external proton hall must sit 9000 ft downstream of the center of the utility straight on the East Campus. For a crystal-extracted beam of 108 protons per second, the beam would simply drift this entire distance to the experimental hall. Some quads might be installed if necessary to transport the beam to the ham or to shape the beam. If at some time in the future the full SSC were to be extracted, this drift could be used to form secondary beamlines for very-high-energy, fixed-target experiments with pion, kaon, or muon beams. In order to accommodate the possibility of full beam extraction, the muon vectors were chosen to be 17,000 more » ft long. The control of the land for this distance assures that no radiation will be allowed to leave the site, regardless of how the program might evolve in the future. This land need only be procured under stratified fee. At the end of this area, some land could be procured on a fee simple basis to provide a space for radiation monitors. This area could also be used ultimately for a future neutrino experiment. « less
122070076
Muon trigger electronics for hadron collider experiments
Abstract Trigger electronics designed and constructed for the SDC muon system are described briefly and results of beam tests carried out at KEK are presented. The implementation is based on custom VLSI designs in 1.2 μm CMOS. The performance characteristics of the circuits were measured and confirmed to meet specifications. Designs based on this approach are applicable to future collider experiments.
124276644
Cross sections for the reactions anti-p + p ---> pi-plus + pi-minus and k-plus + k-minus near 2 gev/c
120121929
Characteristics of the radiation damage seen in the silicon microstrip detector of Fermilab experiment E771
The central region of the silicon microstrip detector used in Fermilab experiment E771 was subjected to a peak fluence of 9.5 × 1013 p/cm2 induced by 800 GeV protons over a two-month period. Fourteen 300 μm thick planes manufactured by Micron Semiconductor were operated at bias voltages ranging from 84 to 109 V. Analysis of data from low intensity beam triggers taken near the end of the run shows that the mean pulse height from our amplifiers began to decline at a fluence of approximately 2 × 1013 p/cm2 and fell to near zero by 6 × 1013 p/cm2. We show that the use of fast amplifiers contributed to this early loss of signal.
60838925
Safety Analysis of the 8-Inch Low Pressure Helium Header System for the Energy Saver