120622268
Status report from VERITAS
VERITAS is a ground-based gamma-ray observatory covering energies between 100 GeV and 50 TeV and will start operating by January 2007. We give a brief report of the construction status and performance characteristics of the telescopes.
17001801
Observation of Extended VHE Emission from the Supernova Remnant IC 443 with VERITAS
We present evidence that the very-high-energy (VHE, E > 100 GeV) gamma-ray emission coincident with the supernova remnant IC 443 is extended. IC 443 contains one of the best-studied sites of supernova remnant/molecular cloud interaction and the pulsar wind nebula CXOU J061705.3+222127, both of which are important targets for VHE observations. VERITAS observed IC 443 for 37.9 hours during 2007 and detected emission above 300 GeV with an excess of 247 events, resulting in a significance of 8.3 standard deviations (sigma) before trials and 7.5 sigma after trials in a point-source search. The emission is centered at 06 16 51 +22 30 11 (J2000) +- 0.03_stat +- 0.08_sys degrees, with an intrinsic extension of 0.16 +- 0.03_stat +- 0.04_sys degrees. The VHE spectrum is well fit by a power law (dN/dE = N_0 * (E/TeV)^-Gamma) with a photon index of 2.99 +- 0.38_stat +- 0.3_sys and an integral flux above 300 GeV of (4.63 +- 0.90_stat +- 0.93_sys) * 10^-12 cm^-2 s^-1. These results are discussed in the context of existing models for gamma-ray production in IC 443.
125665211
Branching fractions in $B \to \phi$ h and search for direct CP violation in $B^\pm \to \phi K^\pm$
9516390
Supernova Acceleration Probe: Studying Dark Energy with Type Ia Supernovae
The Supernova Acceleration Probe (SNAP) will use Type Ia supernovae (SNe Ia) as distance indicators to measure the effect of dark energy on the expansion history of the Universe. (SNAP's weak-lensing program is described in a companion White Paper.) The experiment exploits supernova distance measurements up to their fundamental systematic limit; strict requirements on the monitoring of each supernova's properties lead to the need for a space-based mission. Results from pre-SNAP experiments, which characterize fundamental SN Ia properties, will be used to optimize the SNAP observing strategy to yield data, which minimize both systematic and statistical uncertainties. SNAP has achieved technological readiness and the collaboration is poised to begin construction.
29318124
Discovery of Variability in the Very High Energy γ-Ray Emission of 1ES 1218+304 with VERITAS
We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ~6% of the Crab Nebula flux, the new VERITAS data reveal a prominent flare reaching ~20% of the Crab. While very high energy (VHE) flares are quite common in many nearby blazars, the case of 1ES 1218+304 (redshift z = 0.182) is particularly interesting since it belongs to a group of blazars that exhibit unusually hard VHE spectra considering their redshifts. When correcting the measured spectra for absorption by the extragalactic background light, 1ES 1218+304 and a number of other blazars are found to have differential photon indices Γ≤ 1.5. The difficulty in modeling these hard spectral energy distributions in blazar jets has led to a range of theoretical γ-ray emission scenarios, one of which is strongly constrained by these new VERITAS observations. We consider the implications of the observed light curve of 1ES 1218+304, which shows day scale flux variations, for shock acceleration scenarios in relativistic jets, and in particular for the viability of kiloparsec-scale jet emission scenarios.
120882870
Veritas: Status summary 2009
VERITAS is a ground-based gamma-ray observatory that uses the imaging atmospheric Cherenkov technique and operates in the very-high energy (VHE) region of the gamma-ray spectrum from 100 GeV to 50 TeV. The observatory consists of an array of four 12 m-diameter imaging atmospheric Cherenkov telescopes located in southern Arizona, USA. The four-telescope array has been fully operational since September 2007, and over the last two years, VERITAS has been operating with high reliability and sensitivity. It is currently one of the most sensitive VHE observatories. This paper summarizes the status of VERITAS as of October 2009, and describes the detection of several new VHE gamma-ray sources.
14131306
Search for gravitational waves from low mass compact binary coalescence in 186 days of LIGO's fifth science run
We report on a search for gravitational waves from coalescing compact binaries, of total mass between 2 and 35M⊙, using LIGO observations between November 14, 2006 and May 18, 2007. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass. The LIGO cumulative 90%-confidence rate upper limits of the binary coalescence of neutron stars, black holes and black hole-neutron star systems are 1.4×10-2, 7.3×10-4 and 3.6×10-3  yr-1 L10-1, respectively, where L10 is 1010 times the blue solar luminosity.
181359551
Study of the decay lambda(c)+ ---> Lambda lepton+ lepton-neutrino
9804601
Measurement of the inclusive decay properties of charmed mesons
Abstract We report a high statistics study of the inclusive decay properties of the charmed D 0 and D + mesons, and the first inclusive study of the charmed D s + . The data are collected at s =3.77 GeV and s =4.14 GeV with the Mark III detector at the e + e − storage ring SPEAR. For each charmed meson species, the charged-particle multiplicity, the strangeness content of the final state, and the average π 0 multiplicity are determined.
116536256
Two-body B meson decays to eta and eta-prime Observation of B ---> eta-prime K
124948082
A Study of baryon production in B decay: Search for semileptonic decays of B mesons to charmed baryons and the first observation of Xi(c) production in B decay
Using a high-statistics sample of data on the (4S) resonance and the nearby continuum collected by the CLEO-II detector 1], we have made preliminary studies of: a) correlations of baryons with leptons produced in (4S) ! B B events, and b) direct production of c baryons in B-decay. We nd evidence that the decay b ! cW ? ; W ? ! cs contributes to B-decays to baryons but conclude that the dominant mode for baryon production results from the b ! cW ? ; W ? ! ud transition. Furthermore, based on a study of c ?` and ? ` correlations, our data imply that simple external W-emission does not saturate the entire B !baryons decay width, and that a substantial fraction of the B !baryons rate occurs through internal W-emission.