59382161
QCD subgroup on diffractive and forward physics
Over the last few years, there has been a resurgence of interest in small-x or diffractive physics. This has been due to the realization that perturbative QCD techniques may be applicable to what was previously thought of as a non-perturbative problem and to the opening up of new energy regimes at HERA and the Tevatron collider. The goal is to understand the pomeron, and hence the behavior of total cross sections, elastic scattering and diffractive excitation, in terms of the underlying theory, QCD. This paper is divided into experiments of hadron-hadron colliders and electron-proton colliders.
126196482
ELASTIC SCATTERING OF POSITIVE KAONS ON POLARIZED PROTONS BETWEEN 0.87 AND 2.74 GeV/c. RESULTS AND PHASE-SHIFT ANALYSIS.
Abstract Polarization and differential cross-section data at 16 momenta between 0.86 and 2.74 GeV/ c are presented. (Preliminary data on some of the momenta have been published earlier.) In an energy-independent phase-shift analysis from threshold up to 2.5 GeV/ c , resonant-like as well as non-resonant solutions are found for the P 3 wave. An helicity flip-non-flip decomposition of the partial waves partly supports the indications found in the analyses of other reactions that the pomeron is built up mainly from s -channel helicity non-flip contributions.
118601539
Quartz Cherenkov counters for fast timing: QUARTIC
We have developed particle detectors based on fused silica (quartz) Cherenkov radi- ators read out with microchannel plate photomultipliers (MCP-PMTs) or silicon photomultipliers (SiPMs) for high precision timing (st 10-15 ps). One application is to measure the times of small angle protons from exclusive reactions, p+ p! p+ X + p, at the Large Hadron Collider, LHC. They may also be used to measure directional particle fluxes close to external or stored beams. The detectors have small areas (cm 2 ), but need to be active very close ( 4 mm) to the intense LHC beam, and so must be radiation hard and nearly edgeless. We present results of tests of detectors with quartz bars inclined at the Cherenkov angle, and with bars in the form of an "L" (with a 90 corner). We also describe a possible design for a fast timing hodoscope with few mm 2 elements.
115609427
VIIth Blois Workshop summary: experimental
The Blois Workshop has become a conference not just restricted to diffractive scattering, but including topics such as searches for SUSY and Higgs, measurements of the top mass and b-decays. I will mention these briefly but will mostly discuss new results (and needed future measurements) in hard diffraction at HERA and the Tevatron.
54812349
The Very Large Hadron Collider
I present some of the current ideas about a Very Large Hadron Collider [1] which could eventually extend the high energy frontier beyond that of the Large Hadron Collider (LHC) or any other machine seriously conceived at this time.
125242742
ELASTIC SCATTERING OF POSITIVE PIONS ON POLARIZED PROTONS BETWEEN 0.82 AND 2.74 GeV/c.
Abstract Polarization and differential cross-section data for elastic scattering of positive pions on protons between 0.82 and 2.74 GeV/ c are presented. A dip in the polarization, at constant u ≈ −0.65 GeV 2 , is observed. The data are compared with published phase-shift analyses.
73625238
1318 new variable stars in a 0.25 square degree region of the Galactic plane
We conducted a deep photometric survey of a 0.5 ◦ × 0.5 ◦ area of the Galactic plane using the WFI instrument on the 2.2-m ESO telescope on La Silla, Chile. The dataset comprises a total of 267 R-band images, 204 from a 16 day observation run in 2005, supplemented by 63 images from a six week period in 2002. Our reduction employed the new numerical kernel difference image analysis method as implemented in the pysis3 code and resulted in more than 500 000 lightcurves of stars down to a magnitude limit of R ∼ 24.5. A search for variable stars resulted in the detection of 1318 variables of different types. 1011 of these are eclipsing or contact binary stars. A number of the contact binaries have low mass-ratios and several of the detached binaries appear to have low-mass components. Three candidate contact binaries have periods at the known cut off including two with periods lower than any previously published. Also identified are 3 possible pre-main sequence detached eclipsing binaries.
14344979
The PLANET microlensing follow-up network : results and prospects for the detection of extra-solar planets
Among various techniques to search for extra-solar planets, microlensing has some unique characteristics. Contrary to all other methods which favour nearby objects, microlensing is sensitive to planets around stars at distances of several kpc. These stars act as gravitational lenses leading to a brightening of observed luminous source stars. The lens stars that are tested for the presence of planets are not generally seen themselves. The largest sensitivity is obtained for planets at orbital separations of 1-10 AU offering the view on an extremely interesting range with regard to our own solar system and in particular to the position of Jupiter. The microlensing signal of a jupiter-mass planet lasts typically a few days. This means that a planet reveals its existence by producing a short signal at its quasi-instantaneous position, so that planets can be detected without the need to observe a significant fraction of the orbital period. Relying on the microlensing alerts issued by several survey groups that observe similar to10(7) stars in the Galactic bulge. PLANET (Probing Lensing Anomalies NETwork) performs precise and frequent measurements on ongoing microlensing events in order to detect deviations from a light curve produced by a single point-like object. These measurements allow constraints to be put on the abundance of planets. From 42 well-sampled events between 1995 and 1999, we infer that less than 1/3 of M-dwarfs in the Galactic bulge have jupiter-mass companions at separations between 1 and 4 AU from their parent star, and that
59381191
High-Precision Limb-Darkening Measurement of a K3 Giant Using Microlensing
We obtain high-precision limb-darkening measurements in five bands (V, VE, IE, I, and H) for the K3 III (Teff = 4200 K, [Fe/H] = +0.3, log g = 2.3) source of the Galactic bulge microlensing event EROS BLG-2000-5. These measurements are inconsistent with the predictions of atmospheric models at higher than 10 σ. While the disagreement is present in all bands, it is most apparent in I, IE, and VE, in part because the data are better and in part because the intrinsic disagreement is stronger. We find that when limb-darkening profiles are normalized to have unit total flux, the I-band models for a broad range of temperatures all cross each other at a common point. The solar profile also passes through this point. However, the profile as measured by microlensing does not. We hypothesize that the models have incorporated some aspect of solar physics that is not shared by giant atmospheres.
55031010
Difference image analysis: extension to a spatially varying photometric scale factor and other considerations
We present a general framework for matching the point-spread function (PSF), photometric scaling and sky background between two images, a subject which is commonly referred to as difference image analysis (DIA). We introduce the new concept of a spatially varying photometric scale factor which will be important for DIA applied to wide-field imaging data in order to adapt to transparency and airmass variations across the field-of-view. Furthermore, we demonstrate how to separately control the degree of spatial variation of each kernel basis function, the photometric scale factor and the differential sky background. We discuss the common choices for kernel basis functions within our framework, and we introduce the mixed-resolution delta basis functions to address the problem of the size of the least-squares problem to be solved when using delta basis functions. We validate and demonstrate our algorithm on simulated and real data. We also describe a number of useful optimizations that may be capitalized on during the construction of the least-squares matrix and which have not been reported previously. We pay special attention to presenting a clear notation for the DIA equations which are set out in a way that will hopefully encourage developers to tackle the implementation of DIA software.
16391684
A short, nonplanetary, microlensing anomaly: Observations and light-curve analysis of MACHO 99-BLG-47
We analyze PLANET and MACHO observations of MACHO 99-BLG-47, the first nearly normal microlensing event for which high signal-to-noise ratio data reveal a well-covered, short-duration anomaly. This anomaly occurs near the peak of the event. Short-duration anomalies near the peak of otherwise normal events are expected to arise both from extreme-separation (either very close or very wide), roughly equalmass binary lenses and from planetary systems. We show that the lens of MACHO 99-BLG-47 is in fact an extreme-separation binary, not a planetary system, thus demonstrating for the first time that these two important classes of events can be distinguished in practice. However, we find that the wide-binary and closebinary lens solutions fit the data equally well and cannot be distinguished even at D� 2 ¼ 1. This degeneracy is qualitatively much more severe than the one identified for MACHO 98-SMC-1 because the present degeneracy spans two rather than one dimension in the magnification field and does not require significantly different blending fractions. In the Appendix, we explore this result and show that it is related to the symmetry in the lens equation. Subject headings: binaries: general — gravitational lensing — planetary systems