64 research outputs found
On the influence of the cosmological constant on gravitational lensing in small systems
The cosmological constant Lambda affects gravitational lensing phenomena. The
contribution of Lambda to the observable angular positions of multiple images
and to their amplification and time delay is here computed through a study in
the weak deflection limit of the equations of motion in the Schwarzschild-de
Sitter metric. Due to Lambda the unresolved images are slightly demagnified,
the radius of the Einstein ring decreases and the time delay increases. The
effect is however negligible for near lenses. In the case of null cosmological
constant, we provide some updated results on lensing by a Schwarzschild black
hole.Comment: 8 pages, 1 figure; v2: extended discussion on the lens equation,
references added, results unchanged, in press on PR
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Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider
To reach design luminosity, the International Linear Collider (ILC) must be able to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittances are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 37 nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists
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SciNOvA: A Measurement of Neutrino-Nucleus Scattering in a Narrow-Band Beam
We propose to construct and deploy a fine-grained detector in the Fermilab NOvA 2 GeV narrow-band neutrino beam. In this beam, the detector can make unique contributions to the measurement of quasi-elastic scattering, neutral-current elastic scattering, neutral-current {pi}{sup 0} production, and enhance the NOvA measurements of electron neutrino appearance. To minimize cost and risks, the proposed detector is a copy of the SciBar detector originally built for the K2K long baseline experiment and used recently in the SciBooNE experiment
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ATF2 Proposal Volume 2
For achieving the high luminosity required at the International Linear Collider (ILC), it is critical to focus the beams to nanometer size with the ILC Beam Delivery System (BDS), and to maintain the beam collision with a nanometer-scale stability. To establish the technologies associated with this ultra-high precision beam handling, it has been proposed to implement an ILC-like final focus optics in an extension of the existing extraction beamline of ATF at KEK. The ATF is considered to be the best platform for this exercise, since it provides an adequate ultra-low emittance electron beam in a manner dedicated to the development of ILC. The two major goals for this facility, called ATF2, are: (A) Achievement of a 37 nm beam size, and (B) control of beam position down to 2 nm level. The scientific justification for the ATF2 project and its technical design have been described in Volume 1 of the ATF2 Proposal [1]. We present here Volume 2 of the ATF2 Proposal, in which we present specifics of the construction plans and the group organization to execute the research programs at ATF2. The sections in this report have been authored by relevant ATF2 subgroups within the International ATF Collaboration. The time line of the project is described in Section 2. Section 3 discuss the structure of the international collaboration. Sections 4 and 5 discuss budget considerations, which are presented as well as the design and construction tasks to be shared by the international collaboration at ATF2. Concluding remarks have been contributed by Dr. Ewan Paterson, Chair of the International Collaboration Board of the ATF collaboration
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Measurement of CP Asymmetries and Branching Fractions in Charmless Two-Body B-Meson Decays to Pions and Kaons
We present improved measurements of CP-violation parameters in the decays B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} K{sup +}{pi}{sup -}, and B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and of the branching fractions for B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0} and B{sup 0} {yields} K{sup 0}{pi}{sup 0}. The results are obtained with the full data set collected at the {Upsilon}(4S) resonance by the BABAR experiment at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, corresponding to 467 {+-} 5 million B{bar B} pairs. We find the CP-violation parameter values and branching fractions S{sub {pi}{sup +}{pi}{sup -}} = -0.68 {+-} 0.10 {+-} 0.03, C{sub {pi}{sup +}{pi}{sup -}} = -0.25 {+-} 0.08 {+-} 0.02, {Alpha}{sub K{sup -}{pi}{sup +}} = -0.107 {+-} 0.016{sub -0.004}{sup +0.006}, C{sub {pi}{sup 0}{pi}{sup 0}} = -0.43 {+-} 0.26 {+-} 0.05, {Beta}(B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}) = (1.83 {+-} 0.21 {+-} 0.13) x 10{sup -6}, {Beta}(B{sup 0} {yields} K0{pi}{sup 0}) = (10.1 {+-} 0.6 {+-} 0.4) x 10{sup -6}, where in each case, the first uncertainties are statistical and the second are systematic. We observe CP violation with a significance of 6.7 standard deviations for B{sup 0} {yields} {pi}{sup +}{pi}{sup -} and 6.1 standard deviations for B{sup 0} {yields} K{sup +}{pi}{sup -}, including systematic uncertainties. Constraints on the Unitarity Triangle angle {alpha} are determined from the isospin relations among the B {yields} {pi}{pi} rates and asymmetries. Considering only the solution preferred by the Standard Model, we find {alpha} to be in the range [71{sup o}, 109{sup o}] at the 68% confidence level
Recommended Guidelines for Submission, Trimming, Margin Evaluation, and Reporting of Tumor Biopsy Specimens in Veterinary Surgical Pathology
eoplastic diseases are typically diagnosed by biopsy and histopathological evaluation. The pathology report is key in determining prognosis, therapeutic decisions, and overall case management and therefore requires diagnostic accuracy, completeness, and clarity. Successful management relies on collaboration between clinical veterinarians, oncologists, and pathologists. To date there has been no standardized approach or guideline for the submission, trimming, margin evaluation, or reporting of neoplastic biopsy specimens in veterinary medicine. To address this issue, a committee consisting of veterinary pathologists and oncologists was established under the auspices of the American College of Veterinary Pathologists Oncology Committee. These consensus guidelines were subsequently reviewed and endorsed by a large international group of veterinary pathologists. These recommended guidelines are not mandated but rather exist to help clinicians and veterinary pathologists optimally handle neoplastic biopsy samples. Many of these guidelines represent the collective experience of the committee members and consensus group when assessing neoplastic lesions from veterinary patients but have not met the rigors of definitive scientific study and investigation. These questions of technique, analysis, and evaluation should be put through formal scrutiny in rigorous clinical studies in the near future so that more definitive guidelines can be derived
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Search for b-->u transitions in B- --> DK- and B- --> D*K- Decays
We report results from an updated study of the suppressed decays B{sup -} --> DK{sup -} and B{sup -} --> D*K{sup -} followed by D --> K{sup +}{pi}{sup -}, where D{sup (*)} indicates a D{sup (*)0} or a {anti D}{sup (*)0} meson, and D{sup *} --> D{tau}{sup 0} or D{sup *} --> D{gamma}. These decays are sensitive to the CKM unitarity triangle angle {gamma} due to interference between the b --> c transition B{sup -} --> D{sup (*)0}K{sup -} followed by the double Cabibbo-suppressed decay D{sup 0} --> K{sup +}{pi}{sup -}, and the b --> u transition B{sup -} --> {anti D}{sup (*)0}K{sup -} followed by the Cabibbo-favored decay {anti D}{sup 0} --> K{sup +}{pi}{sup -}. We also report an analysis of the decay B{sup -} --> D{sup (*)}{pi}{sup -} with the D decaying into the doubly Cabibbo-suppressed mode D --> K{sup +}{pi}{sup -}. Our results are based on 467 million {Upsilon}(4S) --> B{anti B} decays collected with the BABAR detector at SLAC. We measure the ratios R{sup (*)} of the suppressed ([K{sup +}{pi}{sup -}]{sub D}K{sup -}/{pi}{sup -}) to favored ([K{sup -}{pi}{sup +}]{sub D}K{sup -}/{pi}{sup -}) branching fractions as well as the CP asymmetries A{sup (*)} of those modes. We see indications of signals for the B{sup -} --> DK{sup -} and B{sup -} --> D{sup *}{sub D{pi}{sup 0}}K{sup -} suppressed modes, with statistical significances of 2.1 and 2.2{sigma}, respectively, and we measure: R{sub DK} = (1.1 {+-} 0.6 {+-} 0.2) x 10{sup -2}, A{sub DK} = -0.86 {+-} 0.47 {sup +0.12}{sub -0.16}, R{sup *}{sub (D{pi}{sup 0})K} = (1.8 {+-} 0.9 {+-} 0.4) x 10{sup -2}, A{sup *}{sub (D{pi}{sup 0})K} = +0.77 {+-} 0.35 {+-} 0.12, R{sup *}{sub (D{gamma})K} = (1.3 {+-} 1.4 {+-} 0.8) x 10{sup -2}, A{sup *}{sub (D{gamma})K} = +0.36 {+-} 0.94 {sup +0.25}{sub -0.41}, where the first uncertainty is statistical and the second is systematic. we use a frequentist approach to obtain the magnitude of the ratio r{sub B} {equivalent_to} {vert_bar}A(B{sup -} --> {anti D}{sup 0}K{sup -})/A(B{sup -} --> D{sup 0}K{sup -}){vert_bar} = (9.5{sup +5.1}{sub -4.1})%, with r{sub B} < 16.7% at 90% confidence level. In the case of B{sup -} --> D{sup *}K{sup -} we find r{sup *}{sub B} {equivalent_to} {vert_bar}A(B{sup -} --> {anti D}{sup *0}K{sup -})/A(B{sup -} --> D{sup *0}K{sup -}){vert_bar} = (9.6{sup +3.5}{sub 5.1})%, with r{sup *}{sub B} < 15.0% at 90% confidence level
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Observation of the decay B0bar -> LambdaC antiproton pi0
In a sample of 467 million B{bar B} pairs collected with the BABAR detector at the PEP-II collider at SLAC we have observed the decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar p}{pi}{sup 0} and measured the branching fraction to be (1.94 {+-} 0.17 {+-} 0.14 {+-} 0.50) x 10{sup -4}, where the uncertainties are statistical, systematic, and the uncertainty on the {Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +} branching fraction, respectively. We determine an upper limit of 1.5 x 10{sup -6} at 90% C.L. for the product branching fraction {Beta}({bar B}{sup 0} {yields} {Sigma}{sub c}{sup +}(2455){bar p}) x {Beta}({Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +}). Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon-antibaryon pair
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Search for CP Violation using T-odd Correlations in D+ to K+K0spi+pi- and DS+ to K+K0spi+pi- Decays
We search for CP violation in a sample of 20,000 Cabibbo-suppressed decays, D{sup +} {yields} K{sup +}K{sub S}{sup 0}{pi}{sup +}{pi}{sup -}, and 30,000 Cabibbo-favored decays, D{sub s}{sup +} {yields} K{sup +}K{sub S}{sup 0}{pi}{sup +}{pi}{sup -}. We use 520 fb{sup -1} of data recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center of mass energies near 10.6 GeV. We search for CP violation in the difference between the T-odd asymmetries obtained using triple product correlations of the D+ (D{sub s}{sup +}) and D{sup -} (D{sub s}{sup -}) decays, respectively. The T violation parameter values obtained are {Alpha}{sub T} (D{sup +}) = (-12.0 {+-} 10.0{sub stat} {+-} 4.6{sub syst}) x 10{sup -3} and {Alpha}{sub T}(D{sub s}{sup +}) = (-13.6 {+-} 7.7{sub stat} {+-} 3.4{sub syst}) x 10{sup -3}, which are consistent with the Standard Model expectations
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Correlated Leading Baryon-antibaryon Production in e+e- to ccbar to Lambda_c+ antiLambda_c- X
We present a study of 649 {+-} 35 e{sup +}e{sup -} {yields} c{bar c} events produced at {radical}s {approx} 10.6 GeV containing both a {Lambda}{sub c}{sup +} baryon and a {bar {Lambda}}{sub c}{sup -} antibaryon. The number observed is roughly four times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2-jet topology in these events but very few additional baryons, demonstrating that the primary c and {bar c} are predominantly contained in a correlated baryon-antibaryon system. In addition to the charmed baryons we observe on average 2.6 {+-} 0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy
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