117199293
Functional-integral approach to chiral anomalies in supersymmetric gauge theories
SummaryWe formulate anomalous chiral and related Ward-Takahashi identities in supersymmetric-gauge theories, by generalizing Fujikawa’s functional-integral method to superspace. Our approach provides a manifestly supersymmetric and gauge-covariant treatment of the superspace Abelian anomalies, and is applicable to chiral- as well as to left-right symmetric theories. Non-Abelian anomalies are also discussed briefly. Superspace Abelian anomalies imply that particular composite operators,i.e. those containing the associatedU1 currents as a component, exhibit an anomalous supermultiplet structure. We discuss how this leads to various exact relations between scalar and gauge fermion condensates, thereby imposing strong constraints on possible chiral-symmetry realizations in supersymmetric-confining theories.RiassuntoSi formulano le identità anomale chirali e correlate di Ward e Takahashi nelle teorie di gauge supersimmetrica, per mezzo della generalizzazione del metodo dell’integrale funzionale di Fujikawa al superspazio. Il nostro approccio fornisce un trattamento manifestamente supersimmetrico e di gauge covariante delle anomalie abeliane del superspazio, ed è applicabile a teorie chirali come pure a teorie simmetriche destresinistre. Si discutono anche brevemente le anomalie non abeliane. Le anomalie abeliane del superspazio implicano che particolari operatori composti, cioè quelli contenenti le correnti associate diU1 come componente, esibiscano una struttura di supermultipletto anomalo. Si discute come ciò porti a varie relazioni esatte tra scalari e condensati di fermioni di gauge, imponendo cosí forti vincoli sulle possibili realizzazioni di simmetria chirale nelle teorie a confinamento supersimmetrico.РеэюмеОбобшая метод функционального интегрирования Фуджикавы на суперпространство, получаются киральные тождества и тождества, родственные тождествам Уорда-Такахащи, в суперсимметричных калибровочных теориях. Предложенный в зтой работе подход для абелевых аномалий является в явном виде суперсимметричным и применим к теориям с киральной симметрией и с лево-правой симметрией. Неабелевы аномалии могут быть рассмотрены аналогичным обраэом, но в зтой работе обсуждаются только вкратце. Абелевы аномалии в суперпространстве подраэумевают аномальную супермультиплетную структуру для некоторых составных операторов. Обсуждается, как зтот подход приводит к раэличным точным соотнощениям, включаюшим скалярный и калибровочно-фермио нный конденсаты и, следовательно, накладываюшим сильные ограничения на реалиэации киральний симметрии (и суперсимметрии) в суперсимметричных удерживаюших теориях.
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.
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.
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.
126281417
QCD Jet calculus
119248886
Subaru Spectroscopy of SDSS-II Supernovae
The Sloan Digital Sky Survey II (SDSS-II) Supernova Survey discovered Type Ia supernovae (SNe Ia) in an almost unexplored intermediate redshift range of $0.05 < z < 0.4$ and provided densely sampled multi-color light curves for SN candidates. Followup spectroscopy of this survey was carried out with the Subaru telescope and spectra of 71 SN Ia candidates were obtained. One spectrum was observed per candidate except for a peculiar variable. This paper presents the method for processing these spectra. The observed wavelength ranges of our spectra are 4000 to 9000 {\AA} for Year 2005 and 3600 to 9000 {\AA} for Year 2006. Most SN Ia spectra have signal to noise ratios (S/N) between 4 and 10 per 2 {\AA} averaged over the entire wavelength region. We developed a new code to extract the SN spectral component from spectra contaminated by the host galaxy. Of 71 SN Ia candidates, 59 are identified as normal SNe Ia and 3 are peculiar SNe Ia. The range of spectral phases varies from -7 days to +30 days from maximum brightness. There are also 7 SNe II, 1 possible hypernova and 1 AGN.
119204401
First-year Sloan Digital Sky Survey-II supernova results: consistency and constraints with other intermediate-redshift data sets
ABSTRACT We present an analysis of the luminosity distances of Type Ia Supernovae (SNe) from the Sloan Digital Sky Survey-II (SDSS-II) SN Survey in conjunction with other intermediate-redshift (z 97 per cent level from this single data set. We find good agreement between the SN and BAO distance measurements, both consistent with a Λ-dominated cold dark matter cosmology, as demonstrated through an analysis of the distance duality relationship between the luminosity (dL) and angular diameter (dA) distance measures. We then use these data to estimate w within this restricted redshift range (z < 0.4). Our most stringent result comes from the combination of all our intermediate-redshift data (SDSS-II SNe, BAO, ISW and redshift-space distortions), giving w = -0.81+0.16-0.18 (stat) +/- 0.15 (sys) and ΩM = 0.22+0.09-0.08 assuming a flat universe. This value of w and associated errors only change slightly if curvature is allowed to vary, consistent with constraints from the cosmic microwave background. We also consider more limited combinations of the geometrical (SN, BAO) and dynamical (ISW, redshift-space distortions) probes.
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.
17597272
The Sloan Digital Sky Survey-II Photometry and Supernova IA Light Curves from the 2005 Data
We present ugriz light curves for 146 spectroscopically-confirmed or spectroscopically-probable Type Ia supernovae (SNe) from the 2005 season of the Sloan Digital Sky Survey-II Supernova (SN) survey. The light curves have been constructed using a photometric technique that we call scene modeling, which is described in detail here; the major feature is that SN brightnesses are extracted from a stack of images without spatial resampling or convolution of the image data. This procedure produces accurate photometry along with accurate estimates of the statistical uncertainty, and can be used to derive photometry taken with multiple telescopes. We discuss various tests of this technique that demonstrate its capabilities. We also describe the methodology used for the calibration of the photometry, and present calibrated magnitudes and fluxes for all of the spectroscopic SNe Ia from the 2005 season.
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.