Phenomenology of Particle Physics Research Papers (original) (raw)

Calculation of the Supersymmetric Higgs Bosons and their detection at CMS.

Somewhat high-quality and comprehensive, but not expressed in math yet.

- by Nathan Coppedge
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- Engineering Physics, Mathematical Physics, Physics, Theoretical Physics

We study the role of the Gauss-Bonnet corrections and two loop higher genus contribution to the gravity action on the Kaluza-Klien modes and their interactions for different bulk fields which enable one to study various phenomenological implications of string loop corrected Gauss-Bonnet modified warped geometry model in one canvas. We have explicitly derived a phenomenological bound on the Gauss-Bonnet parameter so that the required Planck to TeV scale hierarchy can be achieved through the warp factor in the light of recently discovered Higgs like boson at 125 GeV. Moreover due to the presence of small perturbative Gauss-Bonnet as well as string loop corrections we have shown that the warping solution can be obtained for both de-Sitter and anti-de-Sitter bulk which is quite distinct from Randall-Sundrum scenario. Finally we have evaluated various interactions among these bulk fields and determined the coupling parameters and the Kaluza- Klien mode masses which is crucial to understand the phenomenology of a string two loop corrected Einstein-Gauss-Bonnet warp geometry.

- by Sayantan Choudhury
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- Mathematical Physics, Field Theory, Elementary Particle Physics, Gravitation

In this paper we will illustrate how to constrain unavoidable K\"ahler corrections for calN=1{\cal N}=1calN=1 supergravity (SUGRA)
inflation from the recent Planck data. We will show that non-renormalizable K\"ahler operators will induce in general {\it non-minimal kinetic} term for the inflaton field,
and two types of SUGRA corrections in the potential - the {\it Hubble-induced mass} ($c_{H}$), and the {\it Hubble-induced A-term} ($a_{H}$) correction.
The entire SUGRA inflationary framework can now be constrained from (i) {\it speed of sound}, csc_scs, and (ii) from the upper bound on the {\it tensor to scalar ratio}, rstarr_{\star}rstar.
We will illustrate this by considering a heavy scalar degree of freedom at a scale, MsM_sMs, and a light inflationary field which is responsible for a slow-roll inflation. We will compute
the corrections to the kinetic term and the potential explicitly. As an example we will consider a visible sector inflationary model of inflation where inflation occurs at the point
of {\it inflection}, which can match
the density perturbations for the cosmic microwave background radiation, and also explain why the universe is filled with the Standard Model degrees of freedom.
We will scan the parameter space of non-renormalizable K\"ahler operators, which we find them to be order calO(1){\cal O}(1)calO(1), as expected from physical arguments.
While the scale of heavy physics is found to be bounded by the tensor-to scalar ratio and the speed of sound, this high
scale comes out to be varying within a range, $ {\cal O}(10^{11}\leq M_s\leq 10^{16})$~GeV, for the speed of sound varying from 0.02leqcsleq10.02\leq c_s\leq 10.02leqcsleq1, and tensor to scalar
ratio varying from 10−22leqrstarleq0.1210^{-22} \leq r_{\star} \leq 0.1210−22leqrstarleq0.12.

We propose a framework of modulus stabilization in two brane warped geometry scenario in presence of higher curvature gravity and dilaton in bulk space-time. In the prescribed setup we study various features of the stabilized potential for the modulus field, generated by a bulk scalar degrees of freedom with quartic interactions localized on the two 3-branes placed at the orbifold fixed points. We determine the parameter space for the gravidilaton and Gauss-Bonnet required to stabilize the modulus in such higher curvature dilaton gravity setup.

- by Joydip Mitra
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- Physics, Cosmology (Physics), Particle Physics, String Theory

We study the dynamics of relaxation and thermalization in an exactly solvable model with the goal of understanding the eects of o-shell processes. The focus is to compare the exact evolution of the distribution function with dierent approximations to the relaxational dynamics: Boltzmann, non-Markovian and Markovian quantum kinetics. The time evolution of the occupation number or distribution function is evaluated exactly using two methods: time evolution of an initially prepared density matrix and by solving the Heisenberg equations of motion. The former allows to establish a connection with the stochastic nature of thermalization and the uctuation dissipation theorem, whereas the latter leads to the interpretation of an interpolating number operator to`count' quasiparticles. There are two dierent cases that are studied in detail: i) no stable particle states below threshold of the bath and a quasiparticle resonance above it and ii) a stable discrete exact`particle' state below threshold.

- by Richard Holman
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- Field Theory, Physics, Quantum Physics, Kinetics

A generalized quantum kinetic equation (RKE) of the Kadanoff-Baym type is obtained on the basis of the Heisenberg equations of motion where the time evolution and space translation are separated from each other by means of the covariant method. The same approach is used also for a covariant modification of the real-time Green's functions method based on the Wigner representation. The suggested approach does not contain arbitrariness' elements and uncertainties which often arise from derivation of RKE on the basis of the motion equations of the Kadanoff-Baym type for the correlation functions in the case of systems with inner degrees of freedom. Possibilities of the proposed method are demonstrated by examples of derivation of RKE of the Vlasov type and collision integrals of the Boltzmann-Uehling-Uhlenbeck (BUU) type in the frame of the σω-version of quantum hadrodynamics, for the simplest case of spin saturated nuclear matter without antinuclear component. Here, the quasiparticle approximation in a covariant performance is used. A generalization of the method for the description of strong non-equilibrium states based on the non-equilibrium statistical operator is then proposed as well.

- by Giuseppe Maino
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- Mathematics, Quantum Mechanics, Mathematical Sciences, Physical sciences

The isospin mass splittings of the pseudoscalar and vector D and B lightheavy quark system have been calculated using the method of QCD sum rules. Nonperturbative QCD effects are shown to be very small, so that mass splittings arise almost completely from current quark mass splitting and electromagnetic effects, for which a new gauge invariant QED treatment is used. The results are consistent with experiment. A measurement of the isospin splitting of the vector B mesons would give valuable information about quark mass splittings.

- by Zhenping Li
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- High Energy Physics, Phenomenology of Particle Physics, Gauge invariance

The simplest supersymmetric model that solves the µ problem and in which the GUT-scale parameters need not be finely tuned in order to predict the correct value of the Z boson mass at low scales is the Next-to-Minimal Supersymmetric Standard Model (NMSSM). However, in order that fine tuning be absent, the lightest CP-even Higgs boson h should have mass ∼ 100 GeV and SM couplings to gauge bosons and fermions. The only way that this can be consistent with LEP limits is if h decays primarily via h → aa → τ + τ − τ + τ − or 4j but not 4b, where a is the lighter of the two pseudo-scalar Higgses that are present in the NMSSM. Interestingly, m a < 2m b is natural in the NMSSM with m a > 2m τ somewhat preferred. Thus, h → τ + τ − τ + τ − becomes a key mode of interest. Meanwhile, all other Higgs bosons of the NMSSM are typically quite heavy. Detection of any of the NMSSM Higgs bosons at the LHC in this preferred scenario will be very challenging using conventional channels. In this paper, we demonstrate that the h → aa → τ + τ − τ + τ − decay chain should be visible if the Higgs is produced in the process pp → p + h + p with the final state protons being measured using suitably installed forward detectors. Moreover, we show that the mass of both the h and the a can be determined on an event-by-event basis.

We present a classically scale-invariant model where the dark matter, neutrino and electroweak mass scales are dynamically generated from dimensionless couplings. The Standard Model gauge sector is extended by a dark SU(2) X gauge symmetry that is completely broken through a complex scalar doublet via the Coleman-Weinberg mechanism. The three resulting dark vector bosons of equal mass are stable and can play the role of dark matter. We also incorporate right-handed neu-trinos which are coupled to a real singlet scalar that communicates with the other scalars through portal interactions. The multi-Higgs sector is analyzed by imposing theoretical and experimental constraints. We compute the dark matter relic abundance and study the possibility of the direct detection of the dark matter candidate from XENON 1T.

- by Alexandros Karam
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- Particle Physics, Dark Matter, Electroweak Symmetry Breaking, Neutrino Physics

In this paper we will analyze generic predictions of an inflection-point model of inflation with Hubble-induced corrections and study them in light of the Planck data. Typically inflection-point models of inflation can be embedded within Minimal Supersymmetric Standard Model (MSSM) where inflation can occur below the Planck scale. The flexibility of the potential allows us to match the observed amplitude of the TT-power spectrum of the cosmic microwave background radiation with low and high multipoles, spectral tilt, and virtually mild running of the spectral tilt, which can put a bound on an upper limit on the tensor-to-scalar ratio, rleq0.12r \leq 0.12rleq0.12. Since the inflaton within MSSM carries the Standard Model charges, therefore it is the minimal model of inflation beyond the Standard Model which can reheat the universe with the right thermal degrees of freedom without any dark-radiation.

- by Sayantan Choudhury
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- Mathematical Physics, Cosmology (Physics), Gravitation, Particle Physics

One of the drawbacks of conventional grand unification scenarios has been that the unification scale is too high to permit direct exploration. In this paper, we show that the unification scale can be significantly lowered (perhaps even to the TeV scale) through the appearance of extra spacetime dimensions. Such extra dimensions are a natural consequence of string theories with largeradius compactifications. We show that extra spacetime dimensions naturally lead to gauge coupling unification at intermediate mass scales, and moreover may provide a natural mechanism for explaining the fermion mass hierarchy by permitting the fermion masses to evolve with a power-law dependence on the mass scale. We also show that proton-decay constraints may be satisfied in our scenario due to the higher-dimensional cancellation of proton-decay amplitudes to all orders in perturbation theory. Finally, we extend these results by considering theories without supersymmetry; experimental collider signatures; and embeddings into string theory. The latter also enables us to develop several novel methods of explaining the fermion mass hierarchy via D-branes. Our results therefore suggest a new approach towards understanding the physics of grand unification as well as the phenomenology of large-radius string compactifications.

- by Emilian Dudas
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- Mathematical Physics, Physics, Nuclear Physics, Quantum Physics

We investigate the constraints on the flavour violating parameters from the decay B → X s γ, taking into account the interplay of the various sources of flavour violation in the unconstrained MSSM. We present a systematic leading logarithmic QCD analysis of these model-independent constraints, including contributions from gluinos, neutralinos, charginos, charged Higgs bosons and interferences between them. We show that two simple combinations of elements of the down squark mass matrix are stringently bounded over large parts of the parameter space where only weak assumptions on the hierarchical structure of the squark mass matrices are made. We also briefly analyse up to which values SUSY contributions, compatible with B → X s γ, can enhance the Wilson coefficient C 8 (m W), which plays an important role in the phenomenology of charmless hadronic B decays.

- by Tobias Hurth
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- Particle Physics, Phenomenology of Particle Physics, parameter space

We compare recent lattice studies of QCD thermodynamics at non-zero quark chemical potential with the thermodynamics of a hadron resonance gas. We argue that for T ≤ T c the equation of state derived from Monte-Carlo simulations of two flavour QCD at non-zero chemical potential can be well described by a hadron resonance gas when using the same set of approximations as used in current lattice calculations. We estimate the importance of truncation errors arising from the use of a Taylor expansion in terms of the quark chemical potential and examine the influence of unphysically large quark masses on the equation of state and the critical conditions for deconfinement.

Resumen: The history of scientific terminology makes it possible to show 'linguistic changes' or contingency of terms in Science. Husserl's Phenomenology is a complete philosophical framework for elucidating meanings in scientific terminology emphasizing the a priori character of foundational concepts, their contingent aspect (language), intersubjectivity, transcendental subject and epoché. From this point of view, we assume to elucidate the significance of the foundational concepts in physics, taking two of them: ‘Matter’ and ‘Field’. Accessing to knowledge goes through attending to phenomena. The processual character of phenomena can be understood through the Extension-Change ontological categories of Raphael Neelamkavil. This support brings as a natural consequence support for the concept of essence in Husserl as a seminal structure in consciousness that enables knowledge. In this sense, supporting the foundational notions in physics (Matter and Field) under the universal (physical-ontological) categories Extension-Change of Neelamkavil contributes to the Husserlian ideal. Under this support and considering the scientific findings of May-Britt Moser and Edvard Moser (2014) in neuroscience that normalize the Kantian and Husserlian positions around the a priori terms, thus backing physical theories, the importance of Husserlian ideas in physics and philosophy is shown as legitimate linguistic terminology for the a priori understanding of the world. In this way, within the current state of the art, Philipp Berghofer and Harold Wiltsche (2018) address the role of phenomenology in the philosophy of physics; while John Drummond (2019) in Husserl: German Perspectives analyzes the role of phenomenology in Science. Raphael Neelamkavil (2018) reports on a new set of ontological categories in physics that agree with Husserl's ideas in his work Gravitational Coalescense Paradox and Cosmogenetic Causality in Quantum Astrophysical Cosmology. The understanding of the terms ‘Mass’ and ‘Field’ in physics, addresses the study of Hans Grelland Husserl, Einstein and Weyl and Concepts of Space, Time and Space-Time and Hermann Weyl, Space, Matter and Time. A metalinguisitic analysis between scientific and phenomenological terms has not yet been carried out in the history, as well as an adequate relationship between Phenomenon-Subject-Object. The intention of the proposal is to address this blind spot through the triadic Husserl-Weyl-Neelamkavil relationship.

We study the chiral fermion meson model which is the well known linear sigma model of Gell-Mann-and-Levy at finite temperature. A modified self-consistent resummation (MSCR) which resums higher order terms in the perturbative expansion is proposed. It is shown that with the MSCR the problem of tachyonic masses is solved, the renormalization of the gap equations is carried out and the Goldstone's theorem is verified. We also apply the method to investigate another known case at high temperature and compare with results found in the literature.

We examine how large violation of CP and T is allowed in long base line neutrino experiments. When we attribute only the atmospheric neutrino anomaly to neutrino oscillation we may have large CP violating effect. When we attribute both the atmospheric neutrino anomaly and the solar neutrino deficit to neutrino oscillation we may have a sizable T violation effect proportional to the ratio of two mass differences; it is difficult to see CP violation since we can't ignore the matter effect. We give a simple expression for T violation in the presence of matter.

- by Jiro Arafune
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- Mathematical Physics, Physics, Nuclear Physics, Quantum Physics

We present a classically scale-invariant model where the dark matter, neutrino and electroweak mass scales are dynamically generated from dimensionless couplings. The Standard Model gauge sector is extended by a dark SU(2)XSU(2)_XSU(2)X gauge symmetry that is completely broken through a complex scalar doublet via the Coleman-Weinberg mechanism. The three resulting dark vector bosons of equal mass are stable and can play the role of dark matter. We also incorporate right-handed neutrinos which are coupled to a real singlet scalar that communicates with the other scalars through portal interactions. The multi-Higgs sector is analyzed by imposing theoretical and experimental constraints. We compute the dark matter relic abundance and study the possibility of the direct detection of the dark matter candidate from XENON 1T.

- by Alexandros Karam
- •
- Particle Physics, Dark Matter, Electroweak Symmetry Breaking, Neutrino Physics

We estimate the decay width difference ∆Γ d /Γ d in the B d system including 1/m b contributions and next-to-leading order QCD corrections, and find it to be around 0.3%. We explicitly show that the time measurements of an untagged B d decaying to a single final state isotropically can only be sensitive to quadratic terms in ∆Γ d /Γ d , and hence the use of at least two different final states is desired. We discuss such pairs of candidate decay channels for the final states and explore the feasibility of a ∆Γ d /Γ d measurement through them. With tagged decays to CP eigenstates, it is possible to have measurements sensitive to linear terms in ∆Γ d /Γ d with only one final state. The measurement of this width difference is essential for an accurate measurement of sin(2β) at the LHC. The nonzero width difference may also be used to resolve a twofold discrete ambiguity in the B d-B d mixing phase, and hence its measurement is crucial for identifying new physics effects in the mixing. We also derive an upper bound on the value of ∆Γ d /Γ d in the presence of new physics, and point out some differences in the phenomenology of width differences in the B s and B d systems.

We assume that inside the hadrons there are additional partons-tensorgluonswhich carry the same charges as the gluons, but have larger spin. That assumption leads to a possible contribution of polarised tensorgluon density to the spin of the nucleon. The nonzero density of tensorgluons can be created inside a nucleon by radiation of tensorgluons by gluons. Tensorgluons can carry a part of nucleon momentum together with gluons. Because tensorgluons have a larger spin, they can influence the spin structure of the nucleon. This contribution appears in the next to leading order, compared to the gluons and can provide a substantial screening effect due to the larger spin of tensorgluons.

We analyze some consequences of grand unification of the third-generation Yukawa couplings, in the context of the minimal supersymmetric standard model. We address two issues: the prediction of the top quark mass, and the generation of the top-bottom mass hierarchy through a hierarchy of Higgs vacuum expectation values. The top mass is strongly dependent on a certain ratio of superpartner masses. And the VEV hierarchy always entails some tuning of the GUT-scale parameters. We study the RG equations and their semi-analytic solutions, which exhibit several interesting features, such as a focusing effect in the limit of certain symmetries and a correlation between the AAA terms (which contribute to brightarrowsgammab\rightarrow s\gammabrightarrowsgamma) and the gaugino masses. This study shows that non-universal soft-SUSY-breaking masses are favored (in particular for splitting the Higgs doublets via D-terms and for allowing more natural scenarios of symmetry breaking), and hints at features desired in Yukawa-unified models. Several phenomenological implications are also revealed.

- by Uri Sarid
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- Physics, High Energy Physics, Supersymmetry, Phenomenology of Particle Physics

In this paper we introduce an idea of leptogenesis scenario in higher derivative gravity induced DBI Galileon framework {\it aka Galileogenesis} in presence of one-loop R-parity violating couplings in the background of a low energy effective supergravity setup. We have studied extensively the detailed feature of reheating constraints and the cosmophenomenological consequences of thermal gravitino dark matter in light of PLANCK and PDG data. Finally we have also established a direct cosmological connection among dark matter relic abundance, reheating temperature and tensor-to-scalar ratio in the context of DBI Galileon inflation.

- by Sayantan Choudhury
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- Cosmology (Physics), Gravitation, Particle Physics, Observational Cosmology