• Volume 45, Issue S1

October 1995,   pages  1-401

• Preface

• B physics at LEP

The Z factory at LEP is like a mini B factory. About 20% of the time a Z decays to a pair of b flavoured hadrons. As a result, this has provided a major boost to B physics studies. The four sophisticated LEP detectors, with millions of Z events, have provided a variety of interesting results. Only a snapshot of the major developments can be covered in one review. We have considered the results related to$$Z \to b\bar b$$ coupling, in particular, the measurements of Rbbhad the forward backward charge asymmetry. The b hadron properties, like inclusive and exclusive lifetime measurements are summarised briefly. Measurements of$$B^o - B^{ - _o }$$ oscillation parameter as well as the evidence for time dependent evolution have been discussed. Studies of interesting decay modes have been mentioned.

• Limits on 3 boson vertex parameters from LEP200

LEP will be operating at cm energies above W pair threshold from 1996. The process e+e → W+W will provide a unique opportunity to test some important aspects of the Standard Model. The methodology of studying this process has been reviewed in this report. The study of the process will probe at the triple vector boson coupling. The sensitivity to anomalous coupling of W boson has been discussed in detail.

• The effective use of precision electroweak measurements

Several reasonably model-independent formulations of the implications of new physics for precision electroweak measurements have been developed over the past years, most notably by Peskin and Takeuchi, and by Altarelliet al. These formulations work by identifying a small, but useful, set of parameters through which new physics often enters into well-measured physical observables. For the theories to which such an analysis applies, this approach greatly streamlines the confrontation with the data. Since the experimentally-allowed range for these parameters has been determined from global fits to the data, theorists need only compute their predictions for these parameters to constrain their models. We summarize these methods here, together with several recent generalizations which permit applications to wider classes of new physics, and which include the original approaches as special cases.

• CP violation in a multi higgs doublet model

We study CP violation in a multi-Higgs doublet model based on aS3×Z3 horizontal symmetry. We consider two mechanisms for CP violation in this model: a) CP violation due to complex Yukawa couplings; and b) CP violation due to scalarpseudoscalar mixings. We find that the predictions for ε′/ε, CP violation in B decays and the electric dipole moments of neutron and electron are different between these two mechanisms. These predictions are also dramatically different from the minimal Standard Model predictions.

• Phenomenology of the minimal supergravitySU(5) model

The minimal grand unified supergravity model is discussed. Requiring radiative breaking of the electroweak gauge symmetry, the unification ofb and τ Yukawa couplings, a sufficiently stable nucleon, and not too large a relic density of neutralinos produced in the Big Bang constrains the parameter space significantly. In particular, the soft breaking parameterm1/2 has to be less than about 130 GeV, and the top quark Yukawa coupling has to be near its (quasi) fixed point. The former condition implies$$m_{\bar g} \leqslant 400$$ GeV and hence very large production rates for gluino pairs at the LHC, while the latter constraint implies that the lighter stop and sbottom eigenstates are significantly lighter than the other squarks, leading to characteristic signatures for gluino pair events.

• Spontaneous CP violation and neutral B meson decays

A model in which CP is spontaneously broken is described; it solves the strong CP problem and provides an additional mechanism for weak CP violation. This is the aspon model. Application to B decays leads to predictions for CP asymmetries much smaller than expected from the KM mechanism of explicit CP breaking.

• Family symmetry

In this presentation, I discuss an extension of the standard model which is motivated by the desire to allow non-trivial accommodation of three families and is testable by the production of new particles (especially dileptons).

• Determination of mass and width ofW at LEP200

• How good is the quenched approximation of QCD?

The quenched approximation for QCD is, at present and in the foreseeable future, unavoidable in lattice calculations with realistic choices of the lattice spacing, volume and quark masses. In this talk, I review an analytic study of the effects of quenching based on chiral perturbation theory. Quenched chiral perturbation theory leads to quantitative insight on the difference between quenched and unquenched QCD, and reveals clearly some of the diseases which are expected to plague quenched QCD.

• Polarised structure functions

This talk discusses the current understanding in some aspects of polarised lepton-nucleon deep inelastic scattering. The first section focuses on the non-singlet part of available spin dependent structure function data. The results, though consistent with theoretical predictions in this sector, are extremely sensitive to extrapolation of the data to thex→1 region and seem to indicate that the quarksdo carry a very small fraction of the nucleon spin. We then review the formalism of DIS processes with emphasis on the gluon sector.

• Oscillating neutrinos: theory vs experiment

Possible hints on neutrino masses are reviewed. They come from the deficits in the solar as well as atmospheric neutrinos and from need of a significant amount of hot component in the dark matter of the universe. The role of three generation mixing in simultaneously solving the solar and atmospheric neutrino problem is discussed. All the three hints can be reconciled if three neutrinos are almost degenerate. Models for neutrino masses and mixing implied by the above hints are briefly discussed.

• Topics in chiral perturbation theory

I consider some selected topics in chiral perturbation theory (CHPT). For the meson sector, emphasis is put on processes involving pions in the isospin zero S-wave which require multi-loop calculations. The advantages and shortcomings of heavy baryon CHPT are discussed. Some recent results on the structure of the baryons are also presented.

• Threshold effects in SUSY and non-SUSY GUTs

We discuss recent contributions on threshold effects in grand unfiied theories including minimal SUSY SU (5), non-SUSY modifications of the grand desert in SU(5) and SO(10), and SO(10) with single intermediate symmetires. Consequences of theorems on vanishing GUT-scale corrections to sin2 θw in SO(10) with SU(2)L XSU(2)R XSU(4)c (g2l=g2R) intermediate symmetry are discussed and vanishing corrections on the inter-mediate scale are explicitly demonstrated where predictions are more precise. Threshold and higher dimensional operator effects in SUSY SU(5) recently derived by a number of authors are presented.

• Higgs searches and WW scattering

• The inclusive semileptonicB decay lepton spectrum from$$B \to Xe\bar v$$

In this talk, we review the QCD calculations of the lepton spectrum from inclusive semileptonicB decay. We compare this prediction to that of the ACCMM model. This latter work was done in collaboration with Csaba Csaki.

• CP violation at colliders

The prospects of experimental detection ofCP violation ate+e and$$pp/p\bar p$$ colliders are reviewed. After a general discussion on the quantities which can measureCP violation and on the implications of theCPT theorem, various possibilities of measuringCP violation arising outside the standard model are taken up.CP violation in leptonic processes, especially polarization effects ine+el+l are discussed next.CP violation in$$t\overline t$$ andW+W production and decay is also described.

• Structure functions and parton distributions

We review recent developments in the determination of parton densities from deep inelastic and related data. We show how the asymmetries observed in theW± rapidity distributions and inpp/pn Drell-Yan production further constrain the partons at moderatex.

• Physics prospects at the hadron colliders

I start with a brief introduction to the elementary particles and their interactions, Higgs mechanism and supersymmetry. The major physics objectives of the Tevatron and LHC colliders are identified. The status and prospects of the top quark, charged Higgs boson and superparticle searches are discussed in detail, while those of the neutral Higgs boson(s) are covered in a parallel talk by R.J.N. Phillips at this workshop.

• The evolution of the quark-gluon plasma

We survey the different stages in the evolution of the quark-gluon plasma expected to be produced in high energy nuclear collisions, and we discuss some specific experimental probes for each.

• RareK decays

• Testing electroweak vector boson self interactions

We review anomalous triple electroweak vector boson (TEVB) couplings. The anomalous vertex is written in a model independent way and related to the moments of the W boson. Loop-induced bounds on these couplings are derived, including those obtained from the oblique parametersS, T, U. We show that these bounds from oblique parameters in particular, cannot rule out anomalous couplings even if the oblique parameters are in complete agreement with SM. The importance of testing the TEVB vertex beyond LEPI is thereby demonstrated. We examine direct bounds obtainable from theW-radiative andWγ production at CDF and D0 collaborations. However, all the bounds on TEVB to date are too weak to limit most models. It is pointed out that future colliders will be needed to probe loop level SM corrections to the TEVB vertex, as well as examine extensions beyond the SM. A detailed study of the process$$e^ + e^ - \to \ell ^ + \ell ^{\prime - } v\bar v^\prime$$ is carried out with numerical results pressented for the “Next Linear Collider” (NLC) proposed to run at$$\sqrt s = 500GeV$$, 1TeV. We find that the TEVB couplings can be studied accurately enough to probe regions close the loop level corrections within the SM, and also allow for a possibility of separating the photon coupling from that of the Z using polarized beams at the NLC.

• Group report: Collider physics and structure functions

• VLSPs in N=1 SUGRA models

• γγ processes at high energypp colliders

• Triplet higgs bosons ate+e colliders

• Inclusive charm production at HERA and the charm content of the photon

• Group report: Beyond standard model

Working group II at WHEPP3 concentrated on issues related to the super-symmetric standard model as well as SUSY GUTS and neutrino properties. The projects identified by various working groups as well as progress made in them since WHEPP3 are briefly reviewed.

• Group report: Heavy ion physics

• Group report: Heavy flavour physics

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