• Volume 72, Issue 1

January 2009,   pages  1-302

• Preface

• Early physics with ATLAS and CMS

The status of the CMS and ATLAS experiments is given, as it is end of 2007. A quick tour of possible new physics is presented.

• Prospects for Higgs boson searches at the Large Hadron Collider

These proceedings summarize the sensitivity for the CMS and ATLAS experiments at the LHC to discover a Standard Model Higgs boson with relatively low integrated luminosity per experiment. The most relevant discovery modes are dealt with. A brief discussion on the expected performance from these experiments in searches for one or more of the Higgs bosons from the minimal version of the supersymmetric theories is also included.

• Recent relativistic heavy ion collider results on photon, dilepton and heavy quark

We present here a review of the recent results obtained by the RHIC experiments in the framework of QCD under extreme conditions of high temperature or large baryon density, the so-called quark gluon plasma. We focus on a specific category of observables: the electromagnetic probes which cover a large spectrum of experimental studies.

• Electroweak symmetry breaking and beyond the Standard Model physics – A review

In this talk, I shall first discuss the Standard Model Higgs mechanism and then highlight some of its deficiencies making a case for the need to go beyond the Standard Model (BSM). The BSM tour will be guided by symmetry arguments. I shall pick up four specific BSM scenarios, namely, supersymmetry, little Higgs, gauge-Higgs unification, and the Higgsless approach. The discussion will be confined mainly on their electroweak symmetry breaking aspects.

• Transverse spin and momentum correlations in quantum chromodynamics

The naive time reversal odd (T-odd') parton distribution and fragmentation functions are explored. We use the spectator model framework to study flavour dependence of the Boer–Mulders $(h_{1}^{\perp})$ and Sivers $(f_{1\text{T}}^{\perp})$ functions as well as the T-even' but chiral odd function $h_{1\text{L}}^{\perp}$. These transverse momentum-dependent parton distribution functions are of significance for the analysis of azimuthal asymmetries in semi-inclusive deep inelastic scattering, as well as for the overall physical understanding of the distribution of transversely polarized quarks in unpolarized hadrons. In this context we also consider the Collins mechanism and the fragmentation function $H_{1}^{\perp}$. As a by-product of this analysis we calculate the leading twist unpolarized $\cos(2\phi)$ asymmetry, and $\sin(2\phi)$ single spin asymmetry for a longitudinally polarized target in semi-inclusive deep inelastic scattering.

• All-order results for soft and collinear gluons

Some general features and some recent developments concerning the resummation of long-distance singularities in QCD and in more general non-Abelian gauge theories are reviewed. The field-theoretical tools of the trade are emphasized, with the focus mostly on the exponentiation of infra-red and collinear divergences in amplitudes, which underlies the resummation of large logarithms in the corresponding cross-sections. Some recent results concerning the conformal limit, notably the case of $N = 4$ superymmetric Yang–Mills theory are also described.

• Non-collinearity in high energy processes

We discuss the treatment of intrinsic transverse momenta in high energy scattering processes. Within the field theoretical framework of QCD, the process is described in terms of correlators containing quark and gluon fields. The correlators, parametrized in terms of distribution and fragmentation functions, contain matrix elements of nonlo-cal field configurations requiring a careful treatment to assure colour gauge invariance. It leads to nontrivial gauge links connecting the parton fields. For the transverse momentum- dependent correlators the gauge links give rise to time reversal odd phenomena, showing up as single spin and azimuthal asymmetries. The gauge links, arising from multi-gluon initial and final state interactions, depend on the colour flow in the process, challenging universality.

• Charmonium states in quark-gluon plasma

We discuss how the spectral changes of quarkonia at $T_{c}$ can reflect the critical' behaviour of QCD phase transition. Starting from the temperature dependencies of the energy density and pressure from lattice QCD calculation, we extract the temperature dependencies of the scalar and spin-2 gluon condensates near $T_{c}$ . We also parametrize these changes into the electric and magnetic condensate near $T_{c}$. While the magnetic condensate hardly changes across $T_{c}$, we find that the electric condensate increases abruptly above $T_{c}$. Similar abrupt change is also seen in the scalar condensate. Using the QCD second-order Stark effect and QCD sum rules, we show that these sudden changes induce equally abrupt changes in the mass and width of $J/\psi$, both of which are larger than 100 MeV at slightly above $T_{c}$.

• Future of neutrino experiments

Atmospheric, solar, reactor and accelerator neutrino oscillation experiments have measured $\Delta m_{12}^{2}$, $\sin^{2} \theta_{12}$, $|\Delta m_{23}^{2} |$ and $\sin^{2} 2\theta_{23}$ . The next stage of the oscillation studies should be the observation of a finite $\sin^{2} 2\theta_{13}$ . If a non-zero $\sin^{2} 2\theta_{13}$ is observed, the subsequent goals should be the observation of the CP violation and the determination sign of $\Delta m_{23}^{2} . Possible future neutrino oscillation experiments that could assess these questions are discussed. • Neutrino oscillations: Present status and outlook The status of neutrino oscillations from global data is summarized, with the focus on the three-flavour picture. The status of sterile neutrino oscillation interpretations of the LSND anomaly in the light of recent MiniBooNE results is also discussed. Further-more, an outlook on the measurement of the mixing angle$\theta_{13 }$in the near term future, as well as prospects to discover CP violation in neutrino oscillations and to determine the type of the neutrino mass ordering by long-baseline experiments in the long term future are given. • Supersymmetry breaking We review the various mechanisms of supersymmetry breaking and its trans-mission to the observable sector. We argue that hybrid models where gauge dominates over gravity mediation, but gravity provides the main contributions to the Higgs sector masses and the neutralino mass, are able to combine the advantages and reduce the disadvantages of the two transmission mechanisms. • Supersymmetry status and phenomenology at the Large Hadron Collider Large Hadron Collider (LHC) has a great chance to finally reveal supersymmetry which remains a compelling theory for over 30 years in spite of lack of its discovery. It might be around the corner the present LHC era with sensitive dark matter search experiments and international linear collider hopefully coming up in the near future. • Precocious signs of new physics: Are we eight now? Although the CKM-paradigm seems to work to an accuracy of about 15–20%, we emphasize that there are by now several indications that suggest the need for a beyond the Standard Model CP-odd phase. The value of$\sin 2\beta$measured via the gold-plated (tree) mode,$B \rightarrow \psi K_{\text{s}}$is smaller than the value deduced by using improved lattice matrix elements. The value of$\sin 2\beta$measured via penguin-dominated (loop) decays tends to be even smaller still. There is also a rather large difference between the direct CP asymmetries in$\bar{B}^{0} \rightarrow K^{−} \pi^{+}$and$B^{−} \rightarrow K^{−} \pi^{0}$that is rather difficult to understand. More recently, CDF and D0 are finding about a$2\sigma$signal in CP asymmetry in the corresponding gold-plated mode$B_{\text{s}} \rightarrow \psi \phi$. If true, this would be consistent with the indications of new CP-phase in penguin$b \rightarrow s$transitions seen at 𝐵-factories. After describing these possible signs of trouble for the SM-CKM paradigm, we give a brief discussion of some of the BSM scenarios that could be the underlying cause of these deviations. In particular, we find that the data are quite suggestive of a fourth family with$m_{t}^{ˊ} in the range of 400–600 GeV as perhaps the simplest BSM candidate which naturally' explains the data.

• Developments in inflationary cosmology

This talk presents some recent work that has been done in inflationary cosmology. First a brief review is given of the inflation scenario and its basic models. After that, one of the main problems in developing inflationary models has been the requirement of a very flat inflation potential. In solving this problem, supersymmetry has played a major role, and the reasons will be discussed and a specific example of the SUSY hybrid model will be examined. Some problems introduced by SUSY such as the 𝜂 and gravitino problems will then be discussed. Then in a different direction, the quintessential inflation model will be examined as a proposal where a single scalar field plays the role of both the inflaton at early time and the dark energy field later. The final topic covered is developments in understanding dissipation and particle production processes during the inflationary phase.

• The neutrino mass matrix and (selected) variants of A4

Recent neutrino oscillation experiments have measured leptonic mixing angles with considerable precision. Many theoretical attempts to understand the peculiar mixing structure, observed in these measurements, are based on non-Abelian flavour symmetries. This talk concentrates exclusively on models based on the non-Abelian symmetry $A_{4} . A_{4}$ is particularly well suited to describe three family mixing, and allows to explain the near tri-bimaximal mixing observed. Special emphasis is put here on the discussion of the neutrinoless double beta decay observable $\langle m_{\nu} \rangle$ . Different models based on $A_{4}$ with very similar predictions for neutrino angles can yield vastly different expectations for $\langle m_{\nu} \rangle$ . Neutrinoless double beta decay can thus serve, in principle, as a discriminator between different neutrino mass models.

• Challenging the Standard Model with the muon $g − 2$

The discrepancy between experiment and the Standard Model prediction of the muon $g−2$ is reviewed. The possibility to bridge it by hypothetical increases in the hadronic cross-section used to determine the leading hadronic contribution to the latter is analysed.

• $D^{0} - \bar{D}^{0}$ mixing and new physics

The Standard Model (SM) and new physics (NP) descriptions of $D^{0}$ mixing are discussed. The SM part of the discussion addresses both quark-level and hadron-level contributions. The NP part describes our recent works on the rate difference $\Delta \Gamma_{D}$ and the mass difference $\Delta M_{\text{D}}$. In particular, we describe how the recent experimental determination of $\Delta M_{\text{D}}$ is found to place tightened restrictions on parameter spaces for 17 out of the 21 NP models considered.

• The see-saw mechanism: Neutrino mixing, leptogenesis and lepton flavour violation

The see-saw mechanism to generate small neutrino masses is reviewed. After summarizing our current knowledge about the low energy neutrino mass matrix, we consider reconstructing the see-saw mechanism. Indirect tests of see-saw are leptogenesis and lepton flavour violation in supersymmetric scenarios, which together with neutrino mass and mixing define the framework of see-saw phenomenology. Several examples are given, both phenomenological and GUT-related.

• Working group report: Dictionary of Large Hadron Collider signatures

We report on a plan to establish a Dictionary of LHC Signatures', an initiative that started at the WHEPP-X workshop in Chennai, January 2008. This study aims at the strategy of distinguishing 3 classes of dark matter motivated scenarios such as 𝑅-parity conserved supersymmetry, little Higgs models with 𝑇 -parity conservation and universal extra dimensions with KK-parity for generic cases of their realization in a wide range of the model space. Discriminating signatures are tabulated and will need a further detailed analysis.

• Physics beyond Standard Model: Working group 3 report

This is a summary of the beyond the Standard Model (including model building) working group of the WHEPP-X workshop held at Chennai from January 3 to 15, 2008.

• Working group report: Collider and flavour physics

The activities of the working group took place under two broad subgroups: Collider Physics subgroup and Flavour Physics subgroup. Reports on some of the projects undertaken are included. Also, some of the leading discussions organized by the working group are summarized.

• WHEPP-X: Report of the working group on cosmology

This is a summary of the activities of the working group on cosmology at WHEPP-X. The three main problems that were discussed at some length by the group during the course of the workshop were (i) canceling a large' cosmological constant, (ii) non-Gaussianities in inflationary models and (iii) stability of interacting models of dark energy and dark matter. We have briefly outlined these problems and have indicated the progress made.

• Working group report: Neutrino physics

This is the report of the neutrino physics working group at WHEPP-X. We summarize the problems selected and discussed at the workshop and the papers which have resulted subsequently.

• Working group report: Quantum chromodynamics sub-group

This is the report of the QCD working sub-group at the Tenth Workshop on High Energy Physics Phenomenology (WHEPP-X).

• Working group report: Quark gluon plasma

The 10th Workshop on High Energy Physics Phenomenology (WHEPP-10) was held at the Institute of Mathematical Sciences, Chennai during January 2–13, 2008. One of our working grops (WG) is QCD and QGP. The discussions of QGP WG include matter at high density, lattice QCD, charmonium states in QGP, viscous hydrodynamics and jet quenching, colour factor in heavy ion collisions and RHIC results on photons, dileptons and heavy quark. There were two plenary talks and several working group talks with intense discussions regarding the future activities that are going to be persued.

• List of participants

• List of Organisers

• # Pramana – Journal of Physics

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