118571038
Unravelling strings at the CERN LHC
We construct LHC signature footprints for four semirealistic string/M theory vacua with a minimal supersymmetric standard model visible sector. We find that they all give rise to limited regions in LHC signature space and are qualitatively different from each other for understandable reasons. We also propose a technique in which correlations of LHC signatures can be effectively used to distinguish among these string theory vacua. We expect the technique to be useful for more general string vacua. We argue that further systematic analysis with this approach will allow LHC data to disfavor or exclude major 'corners' of string/M theory and favor others. The technique can be used with limited integrated luminosity and improved.
55263386
Higgs Mass Prediction for Realistic String/M Theory Vacua
Recently it has been recognized that in compactified $\mathrm{\text{string}}/M$ theories that satisfy cosmological constraints, it is possible to derive some robust and generic predictions for particle physics and cosmology with very mild assumptions. When the matter and gauge content below the compactification scale is that of the minimal supersymmetric standard model (MSSM), it is possible to make precise predictions. In this case, we predict that there will be a single standard model-like Higgs boson with a calculable mass $105\text{ }\text{ }\mathrm{GeV}\ensuremath{\lesssim}{M}_{h}\ensuremath{\lesssim}129\text{ }\text{ }\mathrm{GeV}$ depending on $\mathrm{tan}﻿\ensuremath{\beta}$ (the ratio of the Higgs vevs in the MSSM). For $\mathrm{tan}﻿\ensuremath{\beta}g7$, the prediction is $122\text{ }\text{ }\mathrm{GeV}\ensuremath{\lesssim}{M}_{h}\ensuremath{\lesssim}129\text{ }\text{ }\mathrm{GeV}$.
5529024
Visible sector supersymmetry breaking revisited
We revisit the possibility of ``visible sector'' SUSY models: models which are straightforward renormalizable extensions of the Minimal Supersymmetric Standard Model (MSSM), where SUSY is broken at tree level. Models of this type were abandoned twenty years ago due to phenomenological problems, which we review. We then demonstrate that it is possible to construct simple phenomenologically viable visible sector SUSY models. Such models are indeed quite constrained, and have some inelegant features. They also have interesting and distinctive phenomenology. Our models predict light gauginos and very heavy squarks and sleptons. The squarks and sleptons may not be observable at the LHC. The LSP is a stable very light gravitino with a significant Higgsino admixture. The NLSP is mostly Bino. The Higgs boson is naturally heavy. Proton decay is sufficently and naturally suppressed, even for a cutoff scale as low as 108 GeV. The lightest particle of the O'Raifeartaigh sector (the LOP) is stable, and is an interesting cold dark matter candidate.
118449988
Electroweak symmetry breaking in the DSSM
A bstractWe study the theoretical and phenomenological consequences of modifying the Kähler potential of the MSSM two Higgs doublet sector. Such modifications naturally arise when the Higgs sector mixes with a quasi-hidden conformal sector, as in some F-theory GUT models. In the Delta-deformed Supersymmetric Standard Model (DSSM), the Higgs fields are operators with non-trivial scaling dimension 1 < Δ < 2. The Kähler metric is singular at the origin of field space due to the presence of quasi-hidden sector states which get their mass from the Higgs vevs. The presence of these extra states leads to the fact that even as Δ → 1, the DSSM does not reduce to the MSSM. In particular, the Higgs can naturally be heavier than the W - and Z-bosons. Perturbative gauge coupling unification, a large top quark Yukawa, and consistency with precision electroweak can all be maintained for Δ close to unity. Moreover, such values of Δ can naturally be obtained in string-motivated constructions. The quasi-hidden sector generically contains states charged under SU(5)GUT as well as gauge singlets, leading to a rich, albeit model-dependent, collider phenomenology.
119200117
The Higgs as a probe of supersymmetric extra sectors
A bstractWe present a general method for calculating the leading contributions to h0 → gg and h0 → γγ in models where the Higgs weakly mixes with a nearly supersymmetric extra sector. Such mixing terms can play an important role in raising the Higgs mass relative to the value expected in the MSSM. Our method applies even when the extra sector is strongly coupled, and moreover does not require a microscopic Lagrangian description. Using constraints from holomorphy we fix the leading parametric form of the contributions to these Higgs processes, including the Higgs mixing angle dependence, up to an overall coefficient. Moreover, when the Higgs is the sole source of mass for a superconformal sector, we show that even this coefficient is often calculable. For appropriate mixing angles, the contribution of the extra states to h0 → gg and h0 → γγ can vanish. We also discuss how current experimental limits already lead to non-trivial constraints on such models. Finally, we provide examples of extra sectors which satisfy the requirements necessary to use the holomorphic approximation.
118469148
Source depth for solar p-modes
Theoretically calculated power spectra are comparable with observed solar p-mode velocity power spectra over a range of mode, degree, and frequency. The depth for the sources responsible for exciting p-modes of frequency 2.0 mHz is determined from the asymmetry of their power spectra and found to be about 800 km below the photosphere for quadrupole sources and 150 km if sources are dipole. The source depth for high-frequency oscillations greater than ~6 mHz is 180 (50) km for quadrupole (dipole) sources.
16614719
Afterglow Emission from Naked Gamma-Ray Bursts
We calculate the afterglow emission for gamma-ray bursts (GRBs) going off in an extremely low density medium, referred to as naked bursts. Our results also apply to the case where the external medium density falls off sharply at some distance from the burst. The observed afterglow flux in this case originates at high latitudes, i.e., where the angle between the fluid velocity and the observer line of sight is greater than Γ-1. The observed peak frequency of the spectrum for naked bursts decreases with observer time as t-1, and the flux at the peak of the spectrum falls off as t-2. The 2-10 keV X-ray flux from a naked burst of average fluence should be observable by the Swift satellite for time duration of about 103 longer than the burst variability timescale. The high-latitude emission contributes to the early X-ray afterglow flux for any GRB, not just naked bursts, and can be separated from the shocked interstellar medium emission by their different spectral and temporal properties. Measurements of the high-latitude emission could be used to map the angular structure of GRB-producing shells.
5888626
Major Surge Activity of Super-Active Region NOAA 10484
We observed two surges in H˛ from the super-active region NOAA 10484. The first surge was associated with an SF/C4.3 class flare. The second one was a major surge associated with a SF/C3.9 flare. This surge was also observedwith SOHO/EIT in 195 A and NoRH in 17 GHz, and showed similar evolution in these wavelengths. The major surge had an ejective funnel-shaped spray structure with fast expansion in linear (about 1:2 × 105 km) and angular (about 65°) size during its maximum phase. The mass motion of the surge was along open magnetic field lines, with average velocity about 100km s−1. The de-twisting motion of the surge reveals relaxation of sheared and twisted magnetic flux. The SOHO/MDI magnetograms reveal that the surges occurred at the site of companion sunspots where positive flux emerged, converged, and canceled against surrounding field of opposite polarity. Our observations support magnetic reconnection models for the surges and jets.
119181202
Template banks to search for low-mass binary black holes in advanced gravitational-wave detectors
Coalescing binary black holes (BBHs) are among the most likely sources for the Laser Interferometer Gravitational-wave Observatory (LIGO) and its international partners Virgo and KAGRA. Optimal searches for BBHs require accurate waveforms for the signal model and effectual template banks that cover the mass space of interest. We investigate the ability of the second-order post-Newtonian TaylorF2 hexagonal template placement metric to construct an effectual template bank, if the template waveforms used are effective one body waveforms tuned to numerical relativity (EOBNRv2). We find that by combining the existing TaylorF2 placement metric with EOBNRv2 waveforms, we can construct an effectual search for BBHs with component masses in the range 3 Msolar = 2.68 radians, there is no significant loss in the total possible signal-to-noise ratio due to neglecting modes other than l = m = 2 in the template waveforms. For a source population uniformly distributed in spacial volume, over the entire sampled region of the component-mass space, the loss in detection rate (averaged over a uniform distribution of inclination angle and sky-location/polarization angles), remains below ~11%. For binaries with high mass-ratios \textit{and} 0.31 <= \iota <= 2.68, including higher order modes could increase the signal-to-noise ratio by as much as 8% in Advanced LIGO. Our results can be used to construct matched-filter searches in Advanced LIGO and Advanced Virgo.
5727567
LOCALIZED HELIOSEISMIC CONSTRAINTS ON SOLAR STRUCTURE
Localized differences between the real Sun and standard solar models are shown to be small. The sound speeds of the real and the standard model Suns typically differ by less than 0.3% for regions of radial width 0.1 R☉ in the solar core.