87 research outputs found
Probing the Higgs portal at the LHC through resonant di-Higgs production
We investigate resonant di-Higgs production as a means of probing extended scalar sectors that include a 125 GeV Standard Model-like Higgs boson. For concreteness, we consider a gauge singlet Higgs portal scenario leading to two mixed doublet-singlet states, h_1,2. For m_h_2 > 2 m_h_1, the resonant di-Higgs production process p p -> h_2 -> h_1 h_1 will lead to final states associated with the decaying pair of Standard Model-like Higgs scalars. We focus on h_2 production via gluon fusion and on the b b tau^+ tau^- final state. We find that discovery of the h_2 at the LHC may be achieved with ~ 100 fb^-1 of integrated luminosity for benchmark parameter choices relevant to cosmology. Our analysis directly maps onto the decoupling limits of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and more generically onto extensions of the Standard Model Higgs sector in which a heavy scalar produced through gluon fusion decays to a pair of Standard Model-like Higgs bosons
Dark Matter with Topological Defects in the Inert Doublet Model
We examine the production of dark matter by decaying topological defects in
the high mass region of the Inert Doublet Model,
extended with an extra U(1) gauge symmetry. The density of dark matter states
(the neutral Higgs states of the inert doublet) is determined by the interplay
of the freeze-out mechanism and the additional production of dark matter states
from the decays of topological defects, in this case cosmic strings. These
decays increase the predicted relic abundance compared to the standard
freeze-out only case, and as a consequence the viable parameter space of the
Inert Doublet Model can be widened substantially. In particular, for a given
dark matter annihilation rate lower dark matter masses become viable. We
investigate the allowed mass range taking into account constraints on the
energy injection rate from the diffuse -ray background and Big Bang
Nucleosynthesis, together with constraints on the dark matter properties coming
from direct and indirect detection limits. For the Inert Doublet Model
high-mass region, an inert Higgs mass as low as GeV is permitted.
There is also an upper limit on string mass per unit length, and hence the
symmetry breaking scale, from the relic abundance in this scenario. Depending
on assumptions made about the string decays, the limits are in the range
GeV to GeV.Comment: 27 pages, 3 figures. V2: Published version with references adde
Radiative neutrino mass generation linked to neutrino mixing and neutrinoless double beta decay predictions
We discuss the connection between the origin of neutrino masses and their mixings which arises in a class of scenarios with radiatively induced neutrino masses. In these scenarios, the neutrino mass matrix acquires textures with two entries close to zero in the basis where the charged-lepton mass matrix is diagonal. This results in specific constraints on the neutrino mixing parameters,which leads to the prediction of (i) a normal ordering of neutrino masses with the lightest neutrino mass in the âŒmeV range, and (ii) testable correlations among the various mixing angles, including a non-zero Ξ13 angle with its exact value correlated with the values of the atmospheric angle Ξ23 and the CP phase ÎŽ. We quantify the impact of deviations from exact zeroes in the mass matrix texture, and connect it to the amount of hierarchy among Yukawa couplings. These scenarios of radiative neutrino mass generation also give rise to new short-range contributions to neutrinoless double beta decay, which dominate over the usual light-neutrino exchange contribution. As a result, this class of models can have a sizable neutrinoless double beta decay rate, in the range of upcoming experiments despite the normal mass ordering of neutrinos
Species Identification of Food Spoilage and Pathogenic Bacteria by MALDI-TOF Mass Fingerprinting
18 pages, 1 table, 2 figuresFood quality and safety is an increasingly important public health issue. Nowadays, the topics âfood qualityâ and âfood safetyâ are very close and two important issues in the food sector, due to the globalization of the food supply and the increased complexity of the food chain. The consumers need to purchase safe products that do not involve any kind of risk for health. On one hand, the aim of the âfood safetyâ is to avoid health hazards for the consumer: microbiological hazards, pesticide residues, misuse of food additives and contaminants, such as chemicals, biological toxins and adulteration. On the other hand, âfood qualityâ includes all attributes that influence the value of a product for the consumer; this includes negative attributes such as spoilage, contamination with filth, discoloration, off-odors and positive attributes such as the origin, color, flavor, texture and processing method of the food (FAO, 2003)This work was funded by project 10PXIB261045PR from Xunta de Galicia and by project AGL2010-19646 from the Spanish Ministry of Science and Technology. The work of K. Böhme and I.C. FernĂĄndez-No is supported by a âMaria Barbeitoâ and âLucas Labradaâ research contract from Xunta de GaliciaN
The Diboson Excess: Experimental Situation and Classification of Explanations; A Les Houches Pre-Proceeding
We examine the `diboson' excess at TeV seen by the LHC experiments
in various channels. We provide a comparison of the excess significances as a
function of the mass of the tentative resonance and give the signal cross
sections needed to explain the excesses. We also present a survey of available
theoretical explanations of the resonance, classified in three main approaches.
Beyond that, we discuss methods to verify the anomaly, determining the major
properties of the various surpluses and exploring how different models can be
discriminated. Finally, we give a tabular summary of the numerous explanations,
presenting their main phenomenological features.Comment: 37 pages, 9 Figures, 1 Tabl
Ngram-based statistical machine translation enhanced with multiple weighted reordering hypotheses
This paper describes the 2007 Ngram-based sta-tistical machine translation system developed at the TALP Research Center of the UPC (Uni-versitat Politecnica de Catalunya) in Barcelona. Emphasis is put on improvements and extensions of the previous years system, being highlighted and empirically compared. Mainly, these include a novel word ordering strategy based on: (1) sta-tistically monotonizing the training source cor-pus and (2) a novel reordering approach based on weighted reordering graphs. In addition, this system introduces a target language model based on statistical classes, a feature for out-of-domain units and an improved optimization procedure. The paper provides details of this system par-ticipation in the ACL 2007 SECOND WORK-SHOP ON STATISTICAL MACHINE TRANSLA-TION. Results on three pairs of languages are reported, namely from Spanish, French and Ger-man into English (and the other way round) for both the in-domain and out-of-domain tasks.
Detection of early-universe gravitational-wave signatures and fundamental physics
Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark discovery, potentially providing a significant clue to some of our most basic, big-picture scientific questions about the Universe. In this white paper, we survey the leading early-Universe mechanisms that may produce a detectable signalâincluding inflation, phase transitions, topological defects, as well as primordial black holesâand highlight the connections to fundamental physics. We review the complementarity with collider searches for new physics, and multimessenger probes of the large-scale structure of the Universe.Peer reviewe
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