• Manuel Drees

Articles written in Pramana – Journal of Physics

• Resolved photon processes

We review high-energy scattering processes that are sensitive to the hadronic structure of the photon, describing theoretical predictions as well as recent experimental results. These processes include deep-inelastic electron-photon scattering ate+e colliders; and the production of jets, heavy quarks and isolated photons in the collision of real photons ate+e colliders, as well as in photon-photon collisions atep colliders. We also comment on minijet based calculations of totalγp andγγ cross-sections, and discuss the possibility that future lineare+e colliders might produce very large photon fluxes due to the beamstrahlung phenomenon; in the most extreme cases, we predict more than one hadronicγγ event to occur at every bunch crossing.

• 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.

• VLSPs in N=1 SUGRA models

• γγ processes at high energypp colliders

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

• Particle dark matter physics: An update

This write-up gives a rather elementary introduction into particle physics aspects of the cosmological dark matter puzzle. A fairly comprehensive list of possible candidates is given; in each case the production mechanism and possible ways to detect them (if any) are described. I then describe detection of the, in my view, most promising candidates, weakly interacting massive particles or WIMPs, in slightly more detail. The main emphasis will be on recent developments.

• Beyond the standard model: Working group report

This report summarises the activities of the working group on ‘Physics beyond the Standard Model’. The results of investigations in incorporatingR-parity in grand unification, the possibility of a light charged Higgs boson in extension of MSSM and radiative generation of neutral vector boson self-couplings within the MSSM are described. Also given is an account of activities in neutrino physics, namely a proposal for a study of the atmospheric muon anomaly in deep underground mines, a field theoretic study of neutrino oscillations and a mechanism to generate appropriate masses of three active plus one sterile neutrino species.

• Particle physics explanations for ultra-high energy cosmic ray events

The origin of cosmic ray events withE ≳ 1011 GeV remains mysterious. In this talk I briefly summarize several proposed particle physics explanations: a breakdown of Lorentz invariance, the ‘Z-burst’ scenario, new hadrons with masses of several GeV as primaries, and magnetic monopoles with mass below 1010 GeV as primaries. I then describe in a little more detail the idea that these events are due to the decays of very massive, long-lived exotic particles.

• # Pramana – Journal of Physics

Volume 94, 2020
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019