2,779 research outputs found
Using jet mass to discover vector quarks at the LHC
We illustrate the utility of jet mass distributions as probes of new physics
at the LHC, focusing on a heavy vector-quark doublet that mixes with the top as
a concrete example. For 1 TeV vector-quark masses, we find that signals with
greater than 5 sigma significance can be achieved after 100 fb^-1. More
generally, jet mass distributions have the potential to provide signals for
heavy states that produce highly boosted weak gauge bosons and/or top quarks.Comment: 7pages, 5 figures; references adde
Light scalar at LHC: the Higgs or the dilaton?
It is likely that the LHC will observe a color- and charge-neutral scalar
whose decays are consistent with those of the Standard Model (SM) Higgs boson.
The Higgs interpretation of such a discovery is not the only possibility. For
example, electroweak symmetry breaking (EWSB) could be triggered by a
spontaneously broken, nearly conformal sector. The spectrum of states at the
electroweak scale would then contain a narrow scalar resonance, the
pseudo-Goldstone boson of conformal symmetry breaking, with Higgs-like
properties. If the conformal sector is strongly coupled, this pseudo-dilaton
may be the only new state accessible at high energy colliders. We discuss the
prospects for distinguishing this mode from a minimal Higgs boson at the LHC
and ILC. The main discriminants between the two scenarios are (1) cubic
self-interactions and (2) a potential enhancement of couplings to massless SM
gauge bosons. A particularly interesting situation arises when the scale f of
conformal symmetry breaking is approximately the electroweak scale v~246 GeV.
Although in this case the LHC may not be able to tell apart a pseudo-dilaton
from the Higgs boson, the self-interactions differ in a way that depends only
on the scaling dimension of certain operators in the conformal sector. This
opens the possibility of using dilaton pair production at future colliders as a
probe of EWSB induced by nearly conformal new physics.Comment: 7 pages, LaTe
The Adaptive Value of Complex Socio-Communicative Behavior
Human spoken language represents the most elaborate communication system, however the selection pressures leading to its emergence are still uncertain. Unlike humans, bonobos and chimpanzees do not have language. However, bonobos may have been subjected to similar selection pressures as early hominins, subsequent to their phylogenetic split from chimpanzees roughly 1.5 million years ago. The current study investigated the similarities and differences in sociality and communicative production between bonobos and chimpanzees in captive settings, using 9, 10-minute focal follows for each individual. Analyses revealed a significant positive correlation between social proximity score and total communicative signals produced, as well as a significant positive correlation between the proportion of time spent playing and total communicative signals produced, for both bonobos and chimpanzees. Additionally, a significant negative correlation was found between the proportion of time spent grooming and total communicative signals produced. Furthermore, a MANOVA indicated a significant species differences in overall communicative production and social proximity score. Specifically, bonobos produced significantly more signals and spent more time in close proximity to conspecifics than chimpanzees. These data are consistent with previous findings that bonobos travel in larger social groups, have greater flexibility in their communicative production, and have the largest communicative repertoires of all non-human ape species. The multifaceted relationship between sociality and communication, and species differences in socio-communicative behavior observed in bonobos and chimpanzees, can provide insight into the evolutionary origins of human spoken language and complex social behavior
Contamination
Soil contamination occurs when substances are added to soil, resulting in increases in concentrations
above background or reference levels. Pollution may follow from contamination when contaminants
are present in amounts that are detrimental to soil quality and become harmful to the environment or
human health. Contamination can occur via a range of pathways including direct application to land and
indirect application from atmospheric deposition.
Contamination was identified by SEPA (2001) as a significant threat to soil quality in many parts of
Scotland. Towers et al. (2006) identified four principal contamination threats to Scottish soils: acidification;
eutrophication; metals; and pesticides. The Scottish Soil Framework (Scottish Government, 2009) set out
the potential impact of these threats on the principal soil functions.
Severe contamination can lead to “contaminated land” [as defined under Part IIA of the Environmental
Protection Act (1990)]. This report does not consider the state and impacts of contaminated land on
the wider environment in detail. For further information on contaminated land, see ‘Dealing with Land
Contamination in Scotland’ (SEPA, 2009).
This chapter considers the causes of soil contamination and their environmental and socio-economic
impacts before going on to discuss the status of, and trends in, levels of contaminants in Scotland’s soils
Standard Model couplings and collider signatures of a light scalar
The electroweak symmetry breaking (EWSB) sector of the Standard Model can be
far richer and more interesting than the usual single scalar doublet model. We
explore scenarios where the EWSB sector is nearly scale invariant and
consequently gives rise to a light CP even scalar particle. The one-doublet SM
is in that category, as are many other models with either weakly or strongly
coupled sectors that trigger EWSB. We study the couplings of the light scalar
to the SM particles that can arise from the explicit breaking of scale
invariance focusing on the possible differences with the minimal SM. The
couplings of the light scalar to light fermions, as well as to the massless
gauge bosons, can be significantly enhanced. We find possible new discovery
channels due to the decays of the conformal scalar into e^+e^- and mu^+mu^-
pairs as well as new production channels via light quark annihilation.Comment: 10 pages, 7 figure
On X-saturated formations of finite groups
This is an Author's Original Manuscript of an article submitted for consideration in Communications in Algebra 33(4):1053-1064 (2005) (copyright Taylor & Francis).
Communications in Algebra is available online at
http://www.tandfonline.com/10.1081/AGB-200053809
DOI 10.1081/AGB-200053809
The final publication is available at link.springer.com[EN] In the paper, a Frattini-like subgroup associated with a class X of simple groups is introduced and analysed. The corresponding X-saturated formations are exactly the X-local ones introduced by Förster. Our techniques are also very useful to highlight the properties and behaviour of omega-local formations. In fact, extensions and improvements of several results of Shemetkov are natural consequences of our study.This work has been supported by Proyecto BFM2001-1667-C03-03, MCyT (Spain) and FEDER (European Union).http://www.tandfonline.com/10.1081/AGB-200053809Ballester Bolinches, A.; Calvo Lopez, C.; Esteban Romero, R. (2005). On X-saturated formations of finite groups. Communications in Algebra. 4(33). doi:10.1081/AGB-20005380943
Social Workers\u27 Perceptions of Family Preservation Programs
The passage of the Adoptions and Safe Families Act of 1997, with its focus on child safety and concurrent planning, has presented family preservation workers with new challenges and new opportunities. Twenty volunteers from a large comprehensive social service agency were interviewed to determine their experiences with two models of family preservation—Multisystemic Therapy (MST) and Traditional Family Preservation Service (TFPS) or practice as usual. Workers from both programs were able to articulate values consistent with family preservation as important strengths of the programs— keeping families together and empowering families for example. Information from referring agencies was described as variable and not especially useful when working with seriously troubled families, especially as it related to risk and child safety. Both groups indicated that the jargon of family preservation had permeated their agencies, and that working with other agencies was at times a challenge, though for different reasons. Finally, despite some reservations about the effectiveness of short-term treatment with families that face serious challenges, both groups of workers were generally satisfied with family preservation as an approach to practice
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