27 research outputs found
Detection prospects of light NMSSM Higgs pseudoscalar via cascades of heavier scalars from vector boson fusion and Higgs-strahlung
No full textA detection at the large hadron collider of a light Higgs pseudoscalar would, if
interpreted in a supersymmetric framework, be a smoking gun signature of nonminimal
supersymmetry. In this work in the framework of the next-to-minimal
supersymmetric standard model we focus on vector boson fusion and Higgs-strahlung
production of heavier scalars that subsequently decay into pairs of light pseudoscalars.
We demonstrate that although these channels have in general very limited reach, they
are viable for the detection of light pseudoscalars in some parts of parameter space and
can serve as an important complementary probe to the dominant gluon-fusion
production mode. We also demonstrate that in a Higgs factory these channels may
reach sensitivities comparable to or even exceeding the gluon fusion channels at the
Large Hadron Collider, thus possibly rendering this our best option to discover a light
pseudoscalar. It is also worth mentioning that for the singlet dominated scalar this may
be the only way to measure its couplings to gauge bosons. Especially promising are
channels where the initial scalar is radiated off a W as these events have relatively high
rates and provide substantial background suppression due to leptons from the W. We
identify three benchmark points that well represent the above scenarios. Assuming that
the masses of the scalars and pseudoscalars are already measured in the gluon-fusion
channel, the event kinematics can be further constrained, hence significantly
improving detection prospects. This is especially important in the Higgs-strahlung
channels with rather heavy scalars, and results in possible detection at 200 fb for the
most favoured parts of the parameter spac
LHC phenomenology of light pseudoscalars in the NMSSM
No full textAfter the discovery of the 125 GeV Higgs boson, the Next-to-Minimal Supersymmetric Standard Model (NMSSM) has become more interesting as a model for new physics since new tree-level contributions to the Higgs mass makes it easier to accommodate the relatively high measured value, as compared to the MSSM. One very distinctive feature of the NMSSM is the possible existence of a light singlet-like pseudoscalar. As this pseudoscalar may be lighter than the discovered Higgs boson without conflict with data, it may lead to LHC signatures rather different to what is usually searched for in terms of new physics. In these proceedings we will discuss studies concerning the discoverability of such light pseudoscalars. It is demonstrated that heavier scalars decaying to pairs of pseudoscalars or pseudoscalars and Z bosons may lead to discovery in a large part of the parameter space. This is especially important for the non-SM like of the two lightest scalars, as it may have an almost 100% branching ratio for decay into pairs of pseudoscalars. In such a case the discussed channels might be our only means of discovery, also for the scalar
A light NMSSM pseudoscalar Higgs boson at the LHC redux
No full textThe Next-to-Minimal Supersymmetric Standard Model (NMSSM) contains a singlet-like pseudoscalar Higgs boson in addition to the doublet-like pseudoscalar of the Minimal Supersymmetric Standard Model. This new pseudoscalar can have a very low mass without violating the LEP exclusion constraints and it can potentially provide a hallmark signature of non-minimal supersymmetry at the LHC. In this analysis we revisit the light pseudoscalar in the NMSSM with partial universality at some high unification scale. We delineate the regions of the model’s parameter space that are consistent with the up-to-date theoretical and experimental constraints, from both Higgs boson searches and elsewhere (most notably b-physics), and examine to what extent they can be probed by the LHC. To this end we review the most important production channels of such a Higgs state and assess the scope of its observation at the forthcoming Run-2 of the LHC. We conclude that the bb-associated production of the pseudoscalar, which has been emphasised in previous studies, does not carry much promise anymore, given the measured mass of the Higgs boson at the LHC. However, the decays of one of the heavier scalar Higgs bosons of the NMSSM can potentially lead to the discovery of its light pseudoscalar. Especially promising are the decays of one or both of the two lightest scalar states into a pseudoscalar pair and of the heaviest scalar into a pseudoscalar and a Z boson. Since the latter channel has not been explored in detail in the literature so far, we provide details of some benchmark points which can be probed for establishing its signature
Review of Higgs-to-light-Higgs searches at the LHC
No full textWe review the most relevant LHC searches at s √ = 8 TeV looking for low mass bosons arising from exotic decay of the Standard Model Higgs and highlighting their impact on both supersymmetric and not supersymmetric Beyond the Standard Model scenarios
Review of LHC experimental results on low mass bosons in multi Higgs models
No full textA variety of searches have been performed at the LHC using Run I data, looking for decays of the discovered Higgs boson, h125, decaying to a pair of low mass bosons, with mass in the range 2mμ−mh125/2≃62 GeV. We summarise the most pertinent ones, and look at how their limits affect a variety of supersymmetric and non-supersymmetric models which can give rise to such light bosons: the 2HDM (Types I and II), the NMSSM, and the nMSSM
A light NMSSM pseudoscalar Higgs boson at the LHC Run 2
No full textWe revisit the light pseudoscalar in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with partial universality at some high unification scale in order to delineate the parameter space regions consistent with up-to-date theoretical and experimental constraints and examine to what extent this state can be probed by the Large Hadron Collider (LHC) during Run 2. We find that it can be accessible through a variety of signatures proceeding via and/or , the former assuming hadronic decays and the latter two -tags within a fat jet or two separate slim ones. Herein, the light pseudoscalar state is produced from a heavy Higgs boson decay in either pairs or singly in association with a boson (in turn decaying into electrons/muons)
Revisiting a light NMSSM pseudoscalar at the LHC
No full textThe discovery of a light, singlet-like pseudoscalar Higgs boson, , of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) could provide a hallmark signature of non-minimal supersymmetry. We review here the potential of the LHC to probe such a light in the decays of one of the heavier scalar Higgs bosons of the NMSSM. We find the production of pairs of the , with a mass below 60 GeV or so, via decays of the two lightest scalar states to be especially promising, for an integrated luminosity as low as 30/fb. For heavier masses, the decay of the heaviest scalar into a boson and an could lead to its detection at the LHC
Gravitino dark matter and the flavour structure of R-violating operators
No full textWe study gravitino dark matter and slow gravitino decays within the framework of R-violating supersymmetry, with particular emphasis on the flavour dependence of the branching ratios and the allowed R-violating couplings. The dominant decay modes and final state products turn out to be very sensitive to the R-violating hierarchies. Mixing effects can be crucial in correctly deriving the relative magnitude of the various contributions, particularly for heavy flavours with phase space suppression. The study of the strength of different decay rates for the gravitino is also correlated to collider signatures expected from decays of the Next-to-Lightest Supersymmetric Particle (NLSP) and to single superparticle production
HISTORIESKRIVNING SOM POLITISKT VERKTYG I UPPLYSNINGENS EUROPA En jämförande analys av Abbé Millot och Catherine Macaulays historiska verk
No full textThe writing of history in Europe went through large changes during the enlightenment. Historians from this epoch could be distinguished by their tendency to try to influence their readers philosophically, morally and politically. The aim of this study is to explore how the historians of the enlightenment could use history writing as a political tool, through a deeper study of the quite forgotten historians Abbé Millot and Catherine Macaulay. Millot was a French historian working at the court of Parma while Macaulay was an English standalone historian. These backgrounds form the aim of this study to fill in a research-gap which still holds the question of how independent a traditional author compared to a standalone author could be in their work. To explore this, this bachelor thesis builds itself upon a comparative text analysis between the historic writings of Millot and Macaulay to explore how they described and discussed historical events, to influence their readers. The result of this analysis shows that Millot and Macaulay portrayed historical events very differently, caused evidently by their own political ideas and goals. It also shows that the larger audience of readers became more relevant to a standalone historian than a historian at court
Review of LHC experimental results on low mass bosons in extended two Higgs doublet models
No full textInternational audienceA number of searches at the LHC looking for low mass () bosons in data have recently beenpublished. We summarise the most pertinent ones, and look at how their limitsaffect a variety of supersymmetric and non-supersymmetric models which can giverise to such light bosons: the 2HDM (Types I and II), the NMSSM, and the nMSSM
