Higgs Mass Prediction with Non-universal Soft Supersymmetry Breaking in MSSM

In the framework of the MSSM the non-universal boundary conditions of soft SUSY breaking parameters are considered. Taking as input the top, bottom and Z-boson masses, the values of the gauge couplings at the EW scale and the infrared quasi-fixed points for Yukawa couplings and the soft parameters the mass of the lightest CP-even Higgs boson is found to be m_h=92.7^{+10}_{-4.9} +- 5 +- 0.4 GeV/c^2 for the low \tan\beta case and m_h=125.7^{+6.4}_{-9.0} +- 5 +- 0.4 GeV/c^2 (\mu > 0) or m_h =125.4^{+6.6}_{-9.0} +-5 +- 0.4 GeV/c^2 (\mu < 0) in the case of large $\tan\beta$.Comment: 12 pages, LaTeX, 12 .eps figures, final versio

Analytical Study of Non-Universality of the Soft Terms in the MSSM

We obtain general analytical forms for the solutions of the one-loop renormalization group equations in the top/bottom/$\tau$ sector of the MSSM. These solutions are valid for any value of $\tan \beta$ as well as any non-universal initial conditions for the soft SUSY breaking parameters and non-unification of the Yukawa couplings. We establish analytically a generic screening effect of non-universality, in the vicinity of the infrared quasi fixed point, which allows to determine sector-wise a hierarchy of sensitivity to initial conditions. We give also various numerical illustrations of this effect away from the quasi fixed point and assess the sensitivity of the Higgs and sfermion spectra to the non-universality of the various soft breaking sectors. As a by-product, a typical anomaly-mediated non-universality of the gaugino sector would have marginal influence on the scalar spectrum.Comment: Latex, 18 pages, 3 figure

Infrared Fixed Point Structure in Minimal Supersymmetric Standard Model with Baryon and Lepton Number Violation

We study in detail the renomalization group evolution of Yukawa couplings and soft supersymmetry breaking trilinear couplings in the minimal supersymmetric standard model with baryon and lepton number violation. We obtain the exact solutions of these equations in a closed form, and then depict the infrared fixed point structure of the third generation Yukawa couplings and the highest generation baryon and lepton number violating couplings. Approximate analytical solutions for these Yukawa couplings and baryon and lepton number violating couplings, and the soft supersymmetry breaking couplings are obtained in terms of their initial values at the unification scale. We then numerically study the infrared fixed surfaces of the model, and illustrate the approach to the fixed points.Comment: 16 pages REVTeX, figures embedded as epsfigs, replaced with version to appear in Physical Review D, minor typographical errors eliminated and references reordered, figures correcte

Nonminimal Supersymmetric Standard Model with Baryon and Lepton Number Violation

We carry out a comprehensive analysis of the nonminimal supersymmetric standard model (NMSSM) with baryon and lepton number violation. We catalogue the baryon and lepton number violating dimension four and five operators of the model. We then study the renormalization group evolution and infrared stable fixed points of the Yukawa couplings and the soft supersymmetry breaking trilinear couplings of this model with baryon and lepton number (and R-parity) violation involving the heaviest generations. We show analytically that in the Yukawa sector of the NMSSM there is only one infrared stable fixed point. This corresponds to a non-trivial fixed point for the top-, bottom-quark Yukawa couplings and the $B$ violating coupling $\lambda_{233}''$, and a trivial one for all other couplings. All other possible fixed points are either unphysical or unstable in the infrared region. We also carry out an analysis of the renormalization group equations for the soft supersymmetry breaking trilinear couplings, and determine the corresponding fixed points for these couplings. We then study the quasi-fixed point behaviour, both of the third generation Yukawa couplings and the baryon number violating coupling, and those of the soft supersymmetry breaking trilinear couplings. From the analysis of the fixed point behaviour, we obtain upper and lower bounds on the baryon number violating coupling $\lambda_{233}''$, as well as on the soft supersymmetry breaking trilinear couplings. Our analysis shows that the infrared fixed point behavior of NMSSM with baryon and lepton number violation is similar to that of MSSM.Comment: 35 pages, Revtex, 6 eps fig

The angular momentum constraint on climate sensitivity and downward influence in the middle atmosphere

It is shown that under reasonable assumptions, conservation of angular momentum provides a strong constraint on gravity wave drag feedbacks to radiative perturbations in the middle atmosphere. In the time mean, radiatively induced temperature perturbations above a given altitude z cannot induce changes in zonal mean wind and temperature below z through feedbacks in gravity wave drag alone (assuming an unchanged gravity wave source spectrum). Thus, despite the many uncertainties in the parameterization of gravity wave drag, the role of gravity wave drag in middle-atmosphere climate perturbations may be much more limited than its role in climate itself. This constraint limits the possibilities for downward influence from the mesosphere. In order for a gravity wave drag parameterization to respect the momentum constraint and avoid spurious downward influence, any nonzero parameterized momentum flux at a model lid must be deposited within the model domain, and there must be no zonal mean sponge layer. Examples are provided of how violation of these conditions leads to spurious downward influence. For planetary waves, the momentum constraint does not prohibit downward influence, but it limits the mechanisms by which it can occur: in the time mean, downward influence from a radiative perturbation can only arise through changes in reflection and meridional propagation properties of planetary waves

Neutralino Dark Matter, b-tau Yukawa Unification and Non-Universal Sfermion Masses

We study the implications of minimal non-Universal Boundary Conditions in the sfermion Soft SUSY Breaking (SSB) masses of mSUGRA. We impose asymptotic b-tau Yukawa coupling Unification and we resort to a parameterization of the deviation from Universality in the SSB motivated by the multiplet structure of SU(5) GUT. A set of cosmo-phenomenological constraints, including the recent results from WMAP, determines the allowed parameter space of the models under consideration. We highlight a new coannihilation corridor where neutralino-sbottom and neutralino-tau sneutrino-stau coannihilations significantly contribute to the reduction of the neutralino relic density.Comment: 38 pages, 27 Figures, Latex; Version accepted for publication in PR

Software history under the lens : a study on why and how developers examine it

Despite software history being indispensable for developers, there is little empirical knowledge about how they examine software history. Without such knowledge, researchers and tool builders are in danger of making wrong assumptions and building inadequate tools. In this paper we present an in-depth empirical study about the motivations developers have for examining software history, the strategies they use, and the challenges they encounter. To learn these, we interviewed 14 experienced developers from industry, and then extended our findings by surveying 217 developers. We found that history does not begin with the latest commit but with uncommitted changes. Moreover, we found that developers had different motivations for examining recent and old history. Based on these findings we propose 3-LENS HISTORY, a novel unified model for reasoning about software history

Mining Continuous Code Changes to Detect Frequent Program Transformations

Identifying repetitive code changes benefits developers, tool builders, and researchers. Tool builders can automate the popular code changes, thus improving the productivity of developers. Researchers would better understand the practice of code evolution, advancing existing code assistance tools even further. Developers would particularly benefit if such tools can learn and support repetitive code changes that are in progress. Unfortunately, the existing tools that aim at detecting frequent code change patterns predominantly focus on analyzing the static source code of an application rather than dynamic code changes, and thus, they can not learn from the changes on-the-fly. We present the first approach that identifies previously unknown frequent code change patterns from a continuous sequence of code changes. Our novel algorithm effectively handles two major challenges that distinguish continuous code change pattern mining from the existing data mining techniques: overlapping transactions and transactions containing multiple instances of the same item kind. We evaluated our algorithm on 1,520 hours of code development collected from 23 developers, and showed that it is effective, useful, and scales to big amounts of data. We analyzed some of the mined code change patterns and discovered ten popular kinds of high-level program transformations.published or submitted for publicationnot peer reviewe

How Do Centralized and Distributed Version Control Systems Impact Software Changes?

Distributed Version Control Systems (DVCS) have seen an increase in popularity relative to traditional Centralized Version Control Systems (CVCS). Yet we know little on whether developers are benefitting from the extra power of DVCS. Without such knowledge, researchers, developers, tool builders, and team managers are in the danger of making wrong assumptions. In this paper we present the first in-depth, large scale empirical study that looks at the influence of DVCS on the practice of splitting, grouping, and committing changes. We recruited 820 participants for a survey that sheds light into the practice of using DVCS. We also analyzed 409M lines of code changed by 358300 commits, made by 5890 developers, in 132 repositories containing a total of 73M LOC. Using this data, we uncovered some interesting facts. For example, (i) commits made in distributed repositories were 32% smaller than the centralized ones, (ii) developers split commits more often in DVCS, and (iii) DVCS commits are more likely to have references to issue tracking labels