Elastic pp Scattering in AdS/CFT

This work is geared towards studying pp collisions using the AdS/CFT correspondence. It is inspired by the work of Richard C. Brower, Joseph Polchinski, Matthew J. Strassler and Chung I Tan (arXiv:1204.0472v1) on particle interactions. A simple extension is provided by calculating the scattering amplitudes of pp collisions using the BPST Pomeron and comparing it to the well known empirical result of elastic pp scattering

Elastic

This work is geared towards studying pp collisions using the AdS/CFT correspondence. It is inspired by the work of Richard C. Brower, Joseph Polchinski, Matthew J. Strassler and Chung I Tan (arXiv:1204.0472v1) on particle interactions. A simple extension is provided by calculating the scattering amplitudes of pp collisions using the BPST Pomeron and comparing it to the well known empirical result of elastic pp scattering

A Phenomenological Model of Effectively Oscillating Massless Neutrinos and Its Implications

We discuss an alternative picture of neutrino oscillation. In this phenomenological model, the flavor-changing phenomena of massless neutrinos arise from scattering processes between neutrinos and four types of undetected spin-0 massive particles pervading throughout the Universe, instead of neutrinos’ own nature. These scattering processes are kinematically similar to Compton scattering. One type of left-handed massless sterile neutrino is needed in order to reproduce the neutrino oscillation modes predicted in the theory of neutrino mixing. Implications of our model include the existence of sterile neu- trinos, the nonconservation of active neutrinos, the possible mismatch among three neutrino mass squared differences ∆m2ij interpreted in the theory of neutrino mixing, the spacetime dependence of neutrino oscillation, and the impossibility of neutrinoless double beta decay. Several important open problems in neutrino physics become trivial or less severe in our model, such as the smallness of neutrino masses, neutrino mass hierarchy, the mechanism responsible for neutrino masses, and the Dirac/Majorana nature of neutrinos

A Phenomenological Model of Effectively Oscillating Massless Neutrinos and Its Implications

We discuss an alternative picture of neutrino oscillation. In this phenomenological model, the flavor-changing phenomena of massless neutrinos arise from scattering processes between neutrinos and four types of undetected spin-0 massive particles pervading throughout the Universe, instead of neutrinos’ own nature. These scattering processes are kinematically similar to Compton scattering. One type of left-handed massless sterile neutrino is needed in order to reproduce the neutrino oscillation modes predicted in the theory of neutrino mixing. Implications of our model include the existence of sterile neu- trinos, the nonconservation of active neutrinos, the possible mismatch among three neutrino mass squared differences ∆m2ij interpreted in the theory of neutrino mixing, the spacetime dependence of neutrino oscillation, and the impossibility of neutrinoless double beta decay. Several important open problems in neutrino physics become trivial or less severe in our model, such as the smallness of neutrino masses, neutrino mass hierarchy, the mechanism responsible for neutrino masses, and the Dirac/Majorana nature of neutrinos

Effect of complex inter-site couplings on the excitation energy transfer in the FMO complex

It is believed that the quantum coherence itself cannot explain the very high excitation energy transfer (EET) efficiency in the Fenna-Matthews-Olson (FMO) complex. In this paper, we show that this is not the case if the inter-site couplings take complex values. By phenomenologically introducing phases into the inter-site couplings, we obtain a EET efficiency as high as 0.8972 in contrast to 0.6781 with real inter-site couplings. Dependence of the EET efficiency on the initial states is elaborated. Effects of fluctuations in the site energies and inter-site couplings are also examined

Analysis of the B s 0 Bs0 B_s^0 → µ+µ– decay in the MSSM

The first observation of the B s 0 $B_s^0$ → µ+µ– decay mode was reported by the CMS and LHCb collaboration. The small branching ratio inherent to this decay mode makes it highly sensitive for probing physics beyond the SM and we analyze this decay in the framework of the Minimal Supersymmetric Standard Model (MSSM). Complete analytical expressions for the decay amplitude at the one-loop order have been obtained with the aid of computational tools such as FeynArts and FeynCalc. The general recipe for utilising these computational tools to aid theoretical calculations in the MSSM is discussed. Working in the phenomenological MSSM with reduced parameter space, a simplification of the complete analytical expression was done to express the B s 0 $B_s^0$ → µ+µ– branching ratio as a function of these parameters. Numerical studies of the parametric dependence of B s 0 $B_s^0$ → µ+µ– branching ratio in the phenomenological MSSM can be easily performed with the obtained analytical expression

Transverse Energy Density in High Energy Heavy Ion Collisions

A phenomenological model describing the transverse energy distribution (ET) of nuclear collisions is first studied in detail by fitting it on ET data for O-Pb collisions at √sNN = 200 GeV per nucleon obtained from the NA35 collaboration. Next, the model is used to fit the ET data for Pb-Pb collisions at LHC energies of √sNN = 2.76 TeV per nucleon obtained from the ATLAS collaboration. From the fits, we determine an upper bound for the energy density for Pb-Pb collisions at LHC energies of √sNN = 2.76 TeV per nucleon

Rapport d'activite - CRPE, annees 1989-1990

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Transverse Energy Density in High Energy Heavy Ion Collisions

A phenomenological model describing the transverse energy distribution (ET) of nuclear collisions is first studied in detail by fitting it on ET data for O-Pb collisions at √sNN = 200 GeV per nucleon obtained from the NA35 collaboration. Next, the model is used to fit the ET data for Pb-Pb collisions at LHC energies of √sNN = 2.76 TeV per nucleon obtained from the ATLAS collaboration. From the fits, we determine an upper bound for the energy density for Pb-Pb collisions at LHC energies of √sNN = 2.76 TeV per nucleon

Nonlinear Dirac Neutrino Oscillations

Neutrino oscillations are a possible way to probe beyond Standard Model physics. The propagation of Dirac neutrinos in a massive medium is governed by the Dirac equation modified with an effective Hamiltonian that de- pends on the number density of surrounding matter fields. At the same time, quantum nonlinearities may contribute to neutrino oscillations by further mod- ifying the Dirac equation. A possible nonlinearity is computationally studied using Mathematica at low energies. We find that the presence of a uniform, static background matter distribution may significantly alter the oscillation am- plitude and wavelength; the considered nonlinearity may further reduce both oscillation amplitude and wavelength. In addition, the presence of matter al- lows the effects of the nonlinearity to be more readily observed for the chosen background densities and neutrino energy