Towards a realistic Standard Model from D-brane configurations

Effective low energy models arising in the context of D-brane configurations with Standard Model (SM) gauge symmetry extended by several gauged abelian factors are discussed. The models are classified according to their hypercharge embeddings consistent with the SM spectrum hypercharge assignment. Particular cases are analyzed according to their perspectives and viability as low energy effective field theory candidates. The resulting string scale is determined by means of a two-loop renormalization group calculation. Their implications in Yukawa couplings, neutrinos and flavor changing processes are also presented.Comment: 22 pages, 12 EPS figures, some clarifications/references adde

W + gamma + jet production as a test of the electromagnetic couplings of W at LHC and SSC

The reaction $pp \to W \ +\ \gamma\ +\ jet \ +\ X$ is considered at centre-of-mass energies $\sqrt{s} = 16$ and 40\;\tev, including anomalous three-gauge-boson couplings $\kappa$ and $\lambda$. The possibility of obtaining limits on these quantities by comparison with the standard model is investigated. The radiation zero properties of the subprocess matrix elements are studied. CERN-TH.6753/92, DTP/92/92.Comment: Latex. 5 figures available (EPS files) on reques

Adjuvant Perioperative Intraperitoneal Chemotherapy in Locally Advanced Colorectal Carcinoma: Preliminary Results

Background and Aims. Intraperitoneal chemotherapy is a basic tool in the treatment of peritoneal malignancy. The purpose of the study is to investigate the effect of adjuvant perioperative intraperitoneal chemotherapy in the treatment of locally advanced colorectal cancer. Patients and Methods. Patients with T3 and T4 colorectal carcinomas that underwent R0 resection received either hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC group = 40 patients) or early postoperative intraperitoneal chemotherapy (EPIC group = 67 patients). The survival, the recurrences and the sites of recurrence were assessed. Results. The 3-year survival rate for HIPEC group was 100% and for EPIC group 69% (P = .011). Nodal infiltration was found to be the single prognostic indicator of survival. The incidence of recurrence in EPIC group was higher than in HIPEC group (P = .009). The independent indicators of recurrence were the use of HIPEC and the degree of differentiation (P < .05). Conclusions. Intraperitoneal chemotherapy, particularly HIPEC, as an adjuvant in locally advanced colorectal carcinomas appears to improve survival and decrease the incidence of recurrence

Inclusive leptoproduction of a transversely polarized baryon on a transversely polarized proton

The processes lp up arrow lY up arrow + X, where Y = Lambda or Sigma(+), are studied, including one-loop higher order corrections (HOC). In constructing the transversity distributions, Soffer’s inequality is taken into account. HOC are found to be small in comparison with those in Drell-Yan l(-)l(+) production by transversely polarized baryons and in transversely polarized baryon-antibaryon production in e(-)e(+) collisions. The reason for this difference is discussed

HEAVY DIQUARK CONTRIBUTIONS TO MULTIJET PRODUCTION AT THE Z0 PEAK

We calculate the contribution of a superstring-inspired heavy diquark to the four-jet rate in e+e- collisions. We find that Z-decay data with charm-quark tagging, corresponding to an integrated luminocity of 20-100 pb-1, will set a bound of 50-60 GeV on the diquark mass. We argue that this is a rather model-independent result

TRANSVERSELY POLARIZED BARYON-ANTIBARYON PRODUCTION IN E(-)E(+) COLLISIONS

Transversely polarized baryon-antibaryon (in particular Lambda-($) over bar Lambda) back-to-back production in e(-)e(+) collisions is studied. Higher order (one-loop) corrections (HOC) are determined and K-factors well exceeding unity are found. For the two cases that the spin vectors of Lambda and ($) over bar Lambda are: (a) on the production plane and (b) perpendicular to it, the differential inclusive cross sections are found to have opposite sign; this feature is characteristic of the process both at the Born and one-loop level, and is independent of the magnitude and shape of the fragmentation functions or other aspects of the calculation. The dominance of HOC by soft, collinear and virtual gluons is also considered