118596941
Higgs in space
We consider the possibility that the Higgs can be produced in dark matter annihilations, appearing as a line in the spectrum of gamma rays at an energy determined by the masses of the WIMP and the Higgs itself. We argue that this phenomenon occurs generally in models in which the the dark sector has large couplings to the most massive states of the SM and provide a simple example inspired by the Randall-Sundrum vision of dark matter, whose 4d dual corresponds to electroweak symmetry-breaking by strong dynamics which respect global symmetries that guarantee a stable WIMP. The dark matter is a Dirac fermion that couples to a Z' acting as a portal to the Standard Model through its strong coupling to top quarks. Annihilation into light standard model degrees of freedom is suppressed and generates a feeble continuum spectrum of gamma rays. Loops of top quarks mediate annihilation into γZ, γh, and γZ', providing a forest of lines in the spectrum. Such models can be probed by the Fermi/GLAST satellite and ground-based Air Cherenkov telescopes.
118462429
Dark matter on top
We consider a simplified model of fermionic dark matter which couples exclusively to the right-handed top quark via a renormalizable interaction with a color-charged scalar. We first compute the relic abundance of this type of dark matter and investigate constraints placed on the model parameter space by the latest direct detection data. We also perform a detailed analysis for the production of dark matter at the LHC for this model. We find several kinematic variables that allow for a clean signal extraction and we show that the parameter space of this model will be well probed during LHC Run-II. Finally, we investigate the possibility of detecting this type of dark matter via its annihilations into gamma rays. We compute the continuum and the line emission (which includes a possible ''Higgs in Space!'' line) and its possible discovery by future gamma-ray telescopes. We find that the annihilation spectrum has distinctive features which may distinguish it from other models.
3163182
Higgs-Pair Production and Measurement of the Triscalar Coupling at LHC(8,14)
Abstract We simulate the measurement of the triscalar Higgs coupling at LHC ( 8 , 14 ) via pair production of h (125 GeV). We find that the most promising hh final state is b b ¯ γ γ . We account for deviations of the triscalar coupling from its SM value and study the effects of this coupling on the hh cross-section and distributions with cut-based and multivariate methods. Our fit to the hh production matrix element at LHC(14) with 3 ab − 1 yields a 30% uncertainty on this coupling in the SM and a range of 20–60% uncertainties for non-SM values.
119298520
The WIMP Forest: Indirect Detection of a Chiral Square
We consider the signals of indirect dark matter detection resulting from a theory of two universal extra dimensions compactified on a chiral square. Aside from the continuum emission, which is a generic prediction of most dark matter candidates, we find a series of prominent annihilation lines (a WIMP forest) that, after convolution with the angular resolution of current experiments, leads to a distinctive (2-bump plus continuum) spectrum, which may be visible in the near future with the Fermi Gamma-Ray Space Telescope (formerly known as GLAST).
125524113
Unitarity and Dark Matter in the Private Higgs Model
18512510
Higgs boson production with one bottom quark including higher-order soft-gluon corrections
A Higgs boson produced in association with one or more bottom quarks is of great theoretical and experimental interest to the high-energy community. A precise prediction of its total and differential cross section can have a great impact on the discovery of a Higgs boson with large bottom-quark Yukawa coupling, like the scalar (h{sup 0} and H{sup 0}) and pseudoscalar (A{sup 0}) Higgs bosons of the minimal supersymmetric standard model in the region of large tan{beta}. In this paper we apply the threshold resummation formalism to determine both differential and total cross sections for bg{yields}b{phi} (where {phi}=h{sup 0},H{sup 0}), including up to next-to-next-to-next-to-leading order soft plus virtual QCD corrections at next-to-leading logarithmic accuracy. We present results for both the Fermilab Tevatron and the CERN Large Hadron Collider.
9747172
The spectral characteristics of the 2 dFGRS – NVSS galaxies
We have analysed the 2dF spectra of a sample of galaxies common to the 2dF galaxy redshift survey (2dFGRS, Colless 1999) and the NRAO VLA sky survey (NVSS, Condon et al. 1998). Our sample comprises 88 galaxies selected by Sadler et al. (1999) from 30 2dFGRS fields observed in 1998. In this paper we discuss how this and future, much larger, samples of 2dFGRS–NVSS galaxies can be interpreted via analysis of those galaxies with strong narrow emission lines. Using diagnostic line ratio measurements we confirm the majority of the eyeball classifications of Sadler et al. (1999), although many galaxies show evidence of being ‘composite’ galaxies – a mixture of AGN plus starburst components.
16781872
Cosmic evolution and unified models for radio AGN
A new method of deriving the cosmological evolution of radio AGN is described which is based on the premise of unified models for quasars and radio galaxies.
14405311
First results from the ATCA 18 GHz pilot survey
ABSTRACT As a pilot study for the ﬁrst all–sky radio survey at short wavelengths, we have ob-served 1216deg 2 of the southern sky at 18GHz (16mm) using a novel wide–band(3.4GHz bandwidth) analogue correlator on one baseline of the Australia TelescopeCompact Array (ATCA). We scanned a region of sky between declination −71 ◦ and−59 ◦ with an rms noise level of 15mJy. Follow–up radio imaging of candidate sourcesabove a 4σ detection limit of 60mJy resulted in 221 conﬁrmed detections, for whichwe have measured accurate positions and ﬂux densities. For extragalactic sources, thesurvey is roughly 70% complete at a ﬂux density of 126mJy and 95% complete above300mJy. Almosthalfthe detected sourceslie within a few degreesofthe Galacticplane,but there are 123 sources with |b| > 5 ◦ which can be assumed to be extragalactic. Thediﬀerential source counts for extragalactic sources in the range 0.1Jy ≤ S 18GHz ≤ 3Jyare well ﬁtted by a relation of the form n(S) = 57(S/Jy) − 2.±0 Jy −1 sr 1 , in goodagreement with the 15GHz counts published by Taylor et al. (2001) and Waldramet al. (2003). Over 70% of the extragalactic sources have a ﬂat radio spectrum(α
121807969
Dark matter search with PICASSO
PICASSO at SNOLAB searches primarily for spin-dependent WIMP interactions on 19F using the superheated droplet technique. This technique is based on the bubble chamber principle, where phase transitions in superheated liquid droplets can be triggered by WIMP induced nuclear recoils. The physics of the detection process allows a highly efficient suppression of backgrounds from cosmic muons, γ- and β-rays. We will discuss qualitatively recent progress in PICASSO and its sensitivity reach for spin-dependent and spin-independent WIMP searches.
119371788
The properties of extragalactic radio sources selected at 20 GHz
We present some first results on the variability, polarization and general properties of radio sources selected at 20 GHz, the highest frequency at which a sensitive radio survey has been carried out over a large area of sky. Sources with flux densities above 100 mJy in the Australia