124438200
Preliminary stereo results from the High Resolution Fly's Eye cosmic ray observatory
The High Resolution Fly's Eye Cosmic Ray Ob- servatory consists of two detector sites located on hilltops in the western desert of Utah. The two sites are separated by 12.6 km. Stereoscopic observations from the two sites en- able the location of air showers to be more accurately recon- structed by using triangulation. The improved geometrical reconstruction provides for a more precise measurement of both the energy of the primary cosmic ray particle and the depth of the shower maximum. Preliminary results from ap- proximately 1000 hours of stereo on-time will be shown.
124185401
Status of the High Altitude Water Cherenkov (HAWC) gamma ray observatory
73632090
Stereo Spectrum of UHECR showers at the HiRes Detector
We present a measurement of the energy spectrum of UHECR showers. This measurement uses the two HiRes detector sites separated by 12.6 km to perform stereoscopic observations of UHECR air showers. The technique of stereoscopic reconstruction of the shower geometry and longitudinal profile is described. The resolution of reconstructed shower parameters using these techniques has been estimated using a detector simulation. Using the independently measured shower profiles from each detector site the energy resolution has also been measured. The detector aperture has been estimated by using the detector simulation. The energy distribution and resultant energy spectrum will be shown.
128530951
Site Characteristics of Southern Utah Sites for Astronomical Observatories
The University of Utah has recently begun construction of a new 0.8 m optical/IR robotic telescope to be operated as a regional astronomy resource in the Intermountain West. The new Southern Utah Observatory (SUO) will require a high altitude (>3000 m) site with excellent atmospheric seeing, favorable weather conditions, and nearby infrastructure, including road, power, and high speed internet. We have explored six possible sites for the SUO telescope with favorable climate, night sky darkness and infrastructure. Since spring 2007, we have performed detailed measurements of atmospheric seeing at several of these sites, and have identified the preferred site for the SUO telescope at Frisco Peak, UT. Several large (1 sq. mile) areas of State Trust Land are nearby the new SUO telescope site. These large, flat areas may be excellent sites for large area, next generation Imaging Atmospheric Cherenkov Telescopes (IACT) arrays such as AGIS or northern CTA.
15877362
A fiber-optic-based calibration system for the High Resolution Fly's Eye cosmic ray observatory
Abstract This article describes the fiber-optic-based calibration system installed at the High Resolution Fly's Eye (HiRes) astro-particle physics observatory. The HiRes detectors measure ultra violet scintillation light from distant extensive air showers. This automated calibration system delivers light from a frequency tripled 355 nm YAG laser to the 10,752 photo-multiplier tubes of the 42 HiRes-II detectors.
117245675
Ultra High Energy nt Detection Using Air Shower Fluorescence/Cerenkov Light Detector
The possibility of using air shower fluorescence/Cerenkov light detectors for ντ detection has been explored. A detector of this type is proposed to be set in the shadow of Mt. Wheeler Peak in Nevada, USA. The ντ to shower conversion probability density is calculated over an energy range from 1 PeV to 10 EeV. The number of showers converted from ντ ’s are estimated according to several models of neutrino sources.
85525002
The Theory of Parity Violation in Few-Nucleon Systems
Abstract We review recent progress in the theoretical description of hadronic parity violation in few-nucleon systems. After introducing the different methods that have been used to study parity-violating observables we discuss the available calculations for reactions with up to five nucleons. Particular emphasis is put on effective field theory calculations where they exist, but earlier and complementary approaches are also presented. We hope this review will serve as a guide for those who wish to know what calculations are available and what further calculations need to be completed before we can claim to have a comprehensive picture of parity violation in few nucleon systems.
118865932
Weak Radiative B Meson Decay
Weak radiative B meson decays, → γX s have a B meson decaying to a hard photon (i.e., E γ ≳ 2 GeV) and strange hadronic final states X s . The prediction of the standard model (with minimal particle content) for the rate for this process is reviewed. Particular attention is paid to the role of strong interaction corrections, which have a significant impact on the rate.
119190019
An effective-field-theory analysis of low-energy parity-violation in nucleon–nucleon scattering
Abstract We analyze parity-violating nucleon–nucleon scattering at energies E m π 2 / M using the effective field theory appropriate for this regime. The minimal Lagrangian for short-range parity-violating NN interactions is written in an operator basis that encodes the five partial-wave transitions that dominate at these energies. We calculate the leading-order relationships between parity-violating NN asymmetries and the coefficients in the Lagrangian and also discuss the size of sub-leading corrections. We conclude with a discussion of further observables needed to completely determine the leading-order Lagrangian.
56337141
Parity-violating neutron spin rotation in hydrogen and deuterium
AbstractWe calculate the (parity-violating) spin-rotation angle of a polarized neutron beam through hydrogen and deuterium targets, using pionless effective field theory up to next-to-leading order. Our result is part of a program to obtain the five leading independent low-energy parameters that characterize hadronic parity violation from few-body observables in one systematic and consistent framework. The two spin-rotation angles provide independent constraints on these parameters. Our result for np spin rotation is $$\frac{1}
{\rho }\frac{{d\varphi _{PV}^{np} }}
{{dl}} = \left[ {4.5 \pm 0.5} \right] rad MeV^{ - \frac{1}
{2}} \left( {2g^{\left( {^3 S_1 - ^3 P_1 } \right)} + g^{\left( {^3 S_1 - ^3 P_1 } \right)} } \right) - \left[ {18.5 \pm 1.9} \right] rad MeV^{ - \frac{1}
{2}} \left( {g_{\left( {\Delta {\rm I} = 0} \right)}^{\left( {^1 S_0 - ^3 P_0 } \right)} - 2g_{\left( {\Delta {\rm I} = 2} \right)}^{\left( {^1 S_0 - ^3 P_0 } \right)} } \right)$$, while for nd spin rotation we obtain $$\frac{1}
{\rho }\frac{{d\varphi _{PV}^{nd} }}
{{dl}} = \left[ {8.0 \pm 0.8} \right] rad MeV^{ - \frac{1}
{2}} g^{\left( {^3 S_1 - ^1 P_1 } \right)} + \left[ {17.0 \pm 1.7} \right] rad MeV^{ - \frac{1}
{2}} g^{\left( {^3 S_1 - ^3 P_1 } \right)} + \left[ {2.3 \pm 0.5} \right] rad MeV^{ - \frac{1}
{2}} \left( {3g_{\left( {\Delta {\rm I} = 0} \right)}^{\left( {^1 S_0 - ^3 P_0 } \right)} - 2g_{\left( {\Delta {\rm I} = 1} \right)}^{\left( {^1 S_0 - ^3 P_0 } \right)} } \right)$$, where the g(X-Y), in units of $$MeV^{ - \frac{3}
{2}}$$, are the presently unknown parameters in the leading-order parity-violating Lagrangian. Using naıve dimensional analysis to estimate the typical size of the couplings, we expect the signal for standard target densities to be $$\left| {\frac{{d\varphi _{PV} }}
{{dl}}} \right| \approx \left[ {10^{ - 7} \ldots 10^{ - 6} } \right]\frac{{rad}}
{m}$$ for both hydrogen and deuterium targets. We find no indication that the nd observable is enhanced compared to the np one. All results are properly renormalized. An estimate of the numerical and systematic uncertainties of our calculations indicates excellent convergence. An appendix contains the relevant partial-wave projectors of the three-nucleon system.
18643814
SU(3) predictions for weak decays of doubly heavy baryons, including SU(3) breaking terms
We find expressions for the weak decay amplitudes of baryons containing two b quarks (or one b and one c quark -- many relationship are the same) in terms of unknown reduced matrix elements. This project was originally motivated by the request of the FNAL Run II b Physics Workshop organizers for a guide to experimentalists in their search for as yet unobserved hadrons. We include an analysis of linear SU(3) breaking terms in addition to relationships generated by unbroken SU(3) symmetry, and relate these to expressions in terms of the complete set of possible reduced matrix elements.