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Register a new userNew features in DPMJET version II.5
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J.Ranft
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DPMJET is a Monte Carlo model for sampling of hadron-hadron, hadron-nucleus, nucleus-nucleus and neutrino-nucleus interactions at accelerator and Cosmic Ray energies according to the two-component Dual Parton Model. Here we describe new features in version DPMJET-II.5: Implementation of new DPM diagrams for an improved description of baryon stopping in nuclear collisions and improvements in the calculation of Glauber cross sections. The new diagrams allow two quite different extrapolations of the model to the highest Cosmic Ray energies. The new version of the model is compared to experimental data on hadron-hadron, hadron-nucleus and nucleus-nucleus collisions.
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DPMJET samples hadron-hadron, hadron-nucleus, nucleus-nucleus and neutrino-nucleus interactions at high energies. The two-component Dual Parton Model is used with multiple soft chains and multiple minijets at each elementary interaction. Particle production is realized by the fragmentation of colorless parton-parton chains constructed from the quark content of the interacting hadrons. DPMJET-II.5 includes the cascading of secondaries within the target as well as projectile nuclei which is suppressed by the formation time concept. The excitation energy of the remaining target and projectile nuclei is calculated and using this nuclear evaporation is included into the model. It is possible to use the model up to primary energies of 10${}^{21}$ eV (per nucleon) in the lab. frame. DPMJET can also be applied to neutrino nucleus collisions. It extends the neutrino-nucleon models qel (quasi elastic neutrino interactions) and lepto (deep inelastic neutrino nucleon collisions) to neutrino collisions on nuclear targets.
We present MadAnalysis 5, an analysis package dedicated to phenomenological studies of simulated collisions occurring in high-energy physics experiments. Within this framework, users are invited, through a user-friendly Python interpreter, to implement physics analyses in a very simple manner. A C++ code is then automatically generated, compiled and executed. Very recently, the expert mode of the program has been extended so that analyses with multiple signal/control regions can be handled. Additional observables have also been included, and an interface to several fast detector simulation packages has been developed, one of them being a tune of the Delphes 3 software. As a result, a recasting of existing ATLAS and CMS analyses can be achieved straightforwardly.
We study the feasibility of realizing supersymmetric new inflation model, introduced by Senoguz and Shafi in [1], for $SU(5)$ and flipped $SU(5)$ models of grand unified theories (GUTs). This realization requires an additional $U(1)_R times Z_{n}$ symmetry for its successful implementation. The standard model (SM) gauge singlet scalar components of $24_H$ and $10_H$ GUT Higgs superfields are respectively employed to realize successful inflation in $SU(5)$ and flipped $SU(5)$ models. The predictions of the various inflationary observables lie within the recent Planck bounds on the scalar spectral index, $n_s$, for $n geq 5$ in $SU(5)$ model and for $n geq 6$ in flipped $SU(5)$ model. In particular, the tensor to scalar ratio $r$ and the running of spectral index $d n_s/ dln k$ are negligibly small and lie in the range, $10^{-12} lesssim r lesssim 10^{-8}$ and $10^{-9} lesssim dn_s/dln k lesssim 10^{-3}$, for realistic values of $n$. In numerical estimation of the various predictions, we fix the gauge symmetry breaking scale, $M$, around $2 times 10^{16}$ GeV. The issue of gauge coupling unification in $R$-symmetric $SU(5)$ is evaded by adding vectorlike families with mass splitting within their multiplets. The dilution of monopoles beyond the observable limit is naturally achieved in the breaking of $SU(5)$ gauge symmetry during inflation. A realistic scenario of reheating with non-thermal leptogenesis is employed for both models. The predicted range of reheat temperature within Planck bounds, $3 times 10^{7}text{ GeV }lesssim T_r lesssim 2 times 10^{9}$ GeV, is safe from the gravitino problem for the gravitino mass, $m_{3/2} gtrsim 10$ TeV. Finally, the $U(1)_R times Z_{n}$ symmetry is also observed to play a crucial role in suppressing the various fast proton decay operators.
This is the second paper on semiclassical approach based on the density matrix given by the Euclidean time path integral with fixed coinciding endpoints. The classical path, interpolating between this point and the classical vacuum, called flucton, plus systematic one- and two-loop corrections, has been calculated in the first paper cite{Escobar-Ruiz:2016aqv} for double-well potential and now extended for a number of quantum-mechanical problems (anharmonic oscillator, sine-Gordon potential). The method is based on systematic expansion in Feynman diagrams and thus can be extended to QFTs. We show that the loop expansion in QM reminds the leading log-approximations in QFT. In this sequel we present complete set of results obtained using this method in unified way. Alternatively, starting from the Schr{o}dinger equation we derive a {it generalized} Bloch equation which semiclassical-like, iterative solution generates the loop expansion. We re-derive two loop expansions for all three above potentials and now extend it to three loops, which has not yet been done via Feynman diagrams. All results for both methods are fully consistent with each other. Asymmetric (tilted) double-well potential (non-degenerate minima) is also studied using the second method.
We map the parameter space that leads to stable Z-vortices in the electroweak model. For $sin^2 theta_W = 0.23$, we find that the strings are unstable for a Higgs mass larger than 24 GeV. Given the latest constraints on the Higgs mass from LEP, this shows that, if the standard electroweak model is realized in Nature, the Z-vortex (in the bare model) is unstable.
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