Kinetic equations for thermal degradation of polymers

Kinetic equations are analyzed for thermal degradation of polymers. The governing relations are based on the fragmentation-annihilation concept. Explicit solutions to these equations are derived in two particular cases of interest. For arbitrary values of adjustable parameters, the evolution of the number-average and mass-average molecular weights of polymers is analyzed numerically. Good agreement is demonstrated between the results of numerical simulation and experimental data. It is revealed that the model can correctly predict observations in thermo-gravimetric tests when its parameters are determined by matching experimental data for the decrease in molecular weight with exposure time

Neutralino relic density in supersymmetric GUTs with no-scale boundary conditions above the unification scale

We investigate SU(5) and SO(10) GUTs with vanishing scalar masses and trilinear scalar couplings at a scale higher than the unification scale. The parameter space of the models, further constrained by b-\tau Yukawa coupling unification, consists of a common gaugino mass and of \tan\beta. We analyze the low energy phenomenology, finding that A-pole annihilations of neutralinos and/or coannihilations with the lightest stau drive the relic density within the cosmologically preferred range in a significant region of the allowed parameter space. Implications for neutralino direct detection and for CERN LHC experiments are also discussed.Comment: 14 pages, 5 figures, JHEP style. Version accepted for publication in JHE

Single Photon Signals for Warped Quantum Gravity at a Linear e+-e- Collider

We study the `single photon' process e+- e- -> gamma nu nubar with contributions due to exchange of massive gravitons in the Randall- Sundrum model of low-scale quantum gravity. It is shown that for significant regions in the parameter space, this process unambiguously highlights the resonance structure of the graviton sector. Even in the non-resonant part of the parameter space, we show that comparison with the benchmark process e+- e- -> mu+- mu- can clearly distinguish signals for warped gravity from similar signals for large extra dimensions.Comment: Published version; figures change

CE16008

The WESPAS survey program is the consolidation of two existing survey programs carried out by FEAS. The Main Shelf herring acoustic survey has been carried out annually since 2008 and reports on the annual abundance of summer feeding aggregations of herring to the west of Scotland and north of Ireland from 54N to 59N. The boarfish survey has been carried out since 2011using a chartered fishing vessel and reports on the abundance of spawning aggregations of boarfish 47N to 57N. In 2016 both surveys were combined and carried out onboard the RV Celtic Explorer over a 42 day period providing synoptic coverage of shelf waters from 59N southwards to 47N

Geometry and BMS Lie algebras of spatially isotropic homogeneous spacetimes

Simply-connected homogeneous spacetimes for kinematical and aristotelian Lie algebras (with space isotropy) have recently been classified in all dimensions. In this paper, we continue the study of these "maximally symmetric" spacetimes by investigating their local geometry. For each such spacetime and relative to exponential coordinates, we calculate the (infinitesimal) action of the kinematical symmetries, paying particular attention to the action of the boosts, showing in almost all cases that they act with generic non-compact orbits. We also calculate the soldering form, the associated vielbein and any invariant aristotelian, galilean or carrollian structures. The (conformal) symmetries of the galilean and carrollian structures we determine are typically infinite-dimensional and reminiscent of BMS Lie algebras. We also determine the space of invariant affine connections on each homogeneous spacetime and work out their torsion and curvature.Comment: 62 pages, 3 figures, 4 tables, v2: Matches published version, mistake corrected in Section 4.1.3., 10.2, 10.3, other minor improvements, added reference

What if Supersymmetry Breaking Unifies beyond the GUT Scale?

We study models in which soft supersymmetry-breaking parameters of the MSSM become universal at some unification scale, $M_{in}$, above the GUT scale, \mgut. We assume that the scalar masses and gaugino masses have common values, $m_0$ and $m_{1/2}$ respectively, at $M_{in}$. We use the renormalization-group equations of the minimal supersymmetric SU(5) GUT to evaluate their evolutions down to \mgut, studying their dependences on the unknown parameters of the SU(5) superpotential. After displaying some generic examples of the evolutions of the soft supersymmetry-breaking parameters, we discuss the effects on physical sparticle masses in some specific examples. We note, for example, that near-degeneracy between the lightest neutralino and the lighter stau is progressively disfavoured as $M_{in}$ increases. This has the consequence, as we show in $(m_{1/2}, m_0)$ planes for several different values of $\tan \beta$, that the stau coannihilation region shrinks as $M_{in}$ increases, and we delineate the regions of the $(M_{in}, \tan \beta)$ plane where it is absent altogether. Moreover, as $M_{in}$ increases, the focus-point region recedes to larger values of $m_0$ for any fixed $\tan \beta$ and $m_{1/2}$. We conclude that the regions of the $(m_{1/2}, m_0)$ plane that are commonly favoured in phenomenological analyses tend to disappear at large $M_{in}$.Comment: 24 pages with 11 eps figures; references added, some figures corrected, discussion extended and figure added; version to appear in EPJ

Relating the CMSSM and SUGRA models with GUT scale and Super-GUT scale Supersymmetry Breaking

While the constrained minimal supersymmetric standard model (CMSSM) with universal gaugino masses, m_{1/2}, scalar masses, m_0, and A-terms, A_0, defined at some high energy scale (usually taken to be the GUT scale) is motivated by general features of supergravity models, it does not carry all of the constraints imposed by minimal supergravity (mSUGRA). In particular, the CMSSM does not impose a relation between the trilinear and bilinear soft supersymmetry breaking terms, B_0 = A_0 - m_0, nor does it impose the relation between the soft scalar masses and the gravitino mass, m_0 = m_{3/2}. As a consequence, tan(\beta) is computed given values of the other CMSSM input parameters. By considering a Giudice-Masiero (GM) extension to mSUGRA, one can introduce new parameters to the K\"ahler potential which are associated with the Higgs sector and recover many of the standard CMSSM predictions. However, depending on the value of A_0, one may have a gravitino or a neutralino dark matter candidate. We also consider the consequences of imposing the universality conditions above the GUT scale. This GM extension provides a natural UV completion for the CMSSM.Comment: 16 pages, 11 figures; added erratum correcting several equations and results in Sec.2, Sec.3 and 4 remain unaffected and conclusions unchange