120289827
Spontaneous breaking of local supersymmetry by gravitational instantons
We study the gravitino condensate 〈(DμΨν − DμΨν)(DμΨν − DνΨμ)〉 in the one-loop approximation around a nontrivial background metric. It turns out that, among the known regular solutions of the euclidean Einstein equations, the Eguchi-Hanson metric is the unique relevant configuration. The standard functional integration gives a finite answer for the gravitino condensate. Due to the presence of an anomalous supersymmetry transformation law, this implies that local supersymmetry is broken spontaneously in all supergravity models with scalar multiplets.
126281417
QCD Jet calculus
121970658
A Simple Algorithm for QCD Jets-An Introduction to Jet Calculus
A new, simple algorithm, recently proposed for QCD jets, is discussed. It allows to compute multiparton distributions inside QCD (q- or g-) jets, within the leading logarithmic approximation. Some of its applications are given.
119485873
A simple algorithm for QCD jets
Abstract A proposal is made, giving multiparticle (parton) spectra inside quark and gluon jets in terms of the tree diagrams of an effective field theory. The resulting “jet calculus” satisfies many consistency checks. A first sample of applications is given.
123003167
Generation of mass hierarchies and gravitational instanton-induced supersymmetry breaking
Consequences of supersymmetry breaking by gravitational instantons are studied in the context of N = 1 supergravity models. In particular, models containing an additional term, proportional to the Euler characteristics density of the spacetime manifold, are shown to lead to a large hierarchy of masses, with the supersymmetry breaking mass scale much smaller than the Planck mass. Possible mechanisms of mass generation for gauge fermions, matter scalars and matter fermions are discussed. Models of this type can arise as a low-energy approximation to superstring models. Our analysis suggests the existence and importance of those nonperturbative effects in the underlying string theories that correspond to the Yang-Mills and gravitational instantons of low-energy effective field theories.
122228895
On the short distance behavior of string theories
Short distance behavior of string theories is investigated by the use of the discretized path-integral formulation. In particular, the minimum physical length and the generalized uncertainty relation are re-derived from a set of Ward–Takahashi identities. Several issues related to the form of the generalized uncertainty relation and to its implications are discussed. A consistent qualitative picture of short distance behavior of string theory seems to emerge from such a study.
118546402
Line Profiles of Intermediate Redshift Type Ia Supernovae
We present the temporal evolution of line profiles ranging from near ultraviolet to optical wavelengths by analyzing 59 Subaru telescope spectra of normal Type Ia Supernovae (SNe Ia) in the intermediate redshift range (0.05 < z < 0.4) discovered by the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. We derive line velocities, peak wavelengths and pseudo-equivalent widths (pEWs) of these lines. Additionally, we compare the line profiles around the date of maximum brightness with those from their nearby counterparts. We find that line profiles represented by their velocities and pEWs for intermediate redshift SNe Ia are consistent with their nearby counterparts within 2 $\sigma$. These findings support the picture that SNe Ia are a "standard" candle for the intermediate redshift range as has been shown between SNe Ia at nearby and high redshifts. There is a hint that the "MgII \lambda 4300" pEW distribution for intermediate redshift SNe Ia is larger than for the nearby sample, which could be interpreted as a difference in the progenitor abundance.
116998818
Circular Statistical Tests for Angular Distributions of Neutrino Burst from SN 1987A and Solar Neutrinos
7368712
SDSS J1029+2623: A Gravitationally Lensed Quasar with an Image Separation of 22.5 Arcseconds
The authors report the discovery of a cluster-scale lensed quasar, SDSS J1029+2623, selected from the Sloan Digital Sky Survey. The lens system exhibits two lensed images of a quasar at z{sub s} = 2.197. The image separation of 22.5 makes it the largest separation lensed quasar discovered to date. The similarity of the optical spectra and the radio loudnesses of the two components support the lensing hypothesis. Images of the field show a cluster of galaxies at z{sub l} {approx} 0.55 that is responsible for the large image separation. The lensed images and the cluster light center are not collinear, which implies that the lensing cluster has a complex structure.
44348672
Type II-P supernovae from the SDSS-II supernova survey and the standardized candle method
We apply the Standardized Candle Method (SCM) for Type II Plateau supernovae (SNe II-P), which relates the velocity of the ejecta of a SN to its luminosity during the plateau, to 15 SNe II-P discovered over the three season run of the Sloan Digital Sky Survey-II Supernova Survey. The redshifts of these SNe—0.027 0.01) as all of the current literature on the SCM combined. We find that the SDSS SNe have a very small intrinsic I-band dispersion (0.22 mag), which can be attributed to selection effects. When the SCM is applied to the combined SDSS-plus-literature set of SNe II-P, the dispersion increases to 0.29 mag, larger than the scatter for either set of SNe separately. We show that the standardization cannot be further improved by eliminating SNe with positive plateau decline rates, as proposed in Poznanski et al. We thoroughly examine all potential systematic effects and conclude that for the SCM to be useful for cosmology, the methods currently used to determine the Fe II velocity at day 50 must be improved, and spectral templates able to encompass the intrinsic variations of Type II-P SNe will be needed.
53135988
The Sloan Digital Sky Survey - II:supernova survey: technical summary
The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5° wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for the discovery of new objects. Supernova imaging observations are being acquired between September 1 and November 30 of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe II, plus a large number of photometrically identified SNe Ia, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.