Searcharxiv⌕ Search

arXiv subjects

G. M. Pruna

Publications and source records attributed to G. M. Pruna.

At least 19 recordsLinked to original sources
arXiv2019

The CLIC Potential for New Physics

The Compact Linear Collider (CLIC) is a mature option for the future of high energy physics. It combines the benefits of the clean environment of $e^+e^-$ colliders with operation at high centre-of-mass energies, allowing to probe scales beyond the reach of the Large Hadron Collider (LHC) for many scenarios of new physics. This places the CLIC project at a privileged spot in between the precision and energy frontiers, with capabilities that will significantly extend knowledge on both fronts at the end of the LHC era. In this report we review and revisit the potential of CLIC to search, directly and indirectly, for physics beyond the Standard Model.

hep-ph↗
arXiv2017

Fully differential NLO predictions for the radiative decay of muons and taus

We present a general purpose Monte Carlo program for the calculation of the radiative muon decay $μ\to e\,ν\barνγ$ and the radiative decays $τ\to e\, ν\barνγ$ and $τ\toμ\,ν\barνγ$ at next-to-leading order in the Fermi theory. The full dependence on the lepton masses and polarization of the initial-sate lepton are kept. We study the branching ratios for these processes and show that fully-differential next-to-leading order corrections are important for addressing a tension between BaBar's recent measurement of the branching ratio $\mathcal{B}(τ\to e\, ν\barνγ)$ and the Standard Model prediction. In addition, we study various distributions of the process $μ\to e\,ν\barνγ$ and obtain precise predictions for the irreducible background to $μ\to e γ$ searches, tailored to the geometry of the MEG detector.

hep-ph↗
arXiv2017

Prospects for charged Higgs searches at the LHC

The goal of this report is to summarize the current situation and discuss possible search strategies for charged scalars, in non-supersymmetric extensions of the Standard Model at the LHC. Such scalars appear in Multi-Higgs-Doublet models (MHDM), in particular in the popular Two-Higgs-Doublet model (2HDM), allowing for charged and additional neutral Higgs bosons. These models have the attractive property that electroweak precision observables are automatically in agreement with the Standard Model at the tree level. For the most popular version of this framework, Model~II, a discovery of a charged Higgs boson remains challenging, since the parameter space is becoming very constrained, and the QCD background is very high. We also briefly comment on models with dark matter which constrain the corresponding charged scalars that occur in these models. The stakes of a possible discovery of an extended scalar sector are very high, and these searches should be pursued in all conceivable channels, at the LHC and at future colliders.

hep-ph↗
arXiv2016

Fully differential NLO predictions for the rare muon decay

Using the automation program GoSam, fully differential NLO corrections were obtained for the rare decay of the muon $μ\to eν\barνee$. This process is an important Standard Model background to searches of the Mu3e collaboration for lepton-flavour violation, as it becomes indistinguishable from the signal $μ\to 3e$ if the neutrinos carry little energy. With our NLO program we are able to compute the branching ratio as well as custom-tailored observables for the experiment. With minor modifications, related decays of the tau can also be computed.

hep-ph↗
arXiv2016

Complementarity in lepton-flavour violating muon decay experiments

This note presents an analysis of lepton-flavour-violating muon decays within the framework of a low-energy effective field theory that contains higher-dimensional operators allowed by QED and QCD symmetries. The decay modes $μ\to e γ$ and $μ\to 3e$ are investigated below the electroweak symmetry-breaking scale, down to energies at which such processes occur, i.e. the muon mass scale. The complete class of dimension-5 and dimension-6 operators is studied systematically at the tree level, and one-loop contributions to the renormalisation group equations are fully taken into account. Current experimental limits are used to extract bounds on the Wilson coefficients of some of the operators and, ultimately, on the effective couplings at any energy level below the electroweak symmetry-breaking scale. Correlations between two couplings relevant to both processes illustrate the complementarity of searches planned for the MEG II and Mu3e experiments.

hep-ph↗
arXiv2015

Composite Higgs models and $t\bar t$ production at future $e^+e^-$ colliders

The study of the top quark properties will be an integral part of any particle physics activity at future leptonic colliders. In this proceeding we discuss the possibility of testing composite Higgs scenarios at $e^+e^-$ prototypes through deviations from the Standard Model predictions in $t\bar t$ production observables for various centre of mass energies, ranging from 370 GeV up to 1 TeV. This proceedings draws from Ref. arXiv:1504.05407

hep-ph↗
arXiv2014

Composite Higgs searches at the LHC and beyond

General Composite Higgs models provide an elegant solution to the hierarchy problem present in the Standard Model and give an alternative pattern leading to the mechanism of electroweak (EW) symmetry breaking. We present an analysis of a realistic realization of this general idea, namely the 4DCHM, analysing the Higgs production and decay modes, fitting them to the latest LHC showing the compatibility with the results of the CERN machine. We then present the prospects of a future electron positron collider of testing this model against the expected experimental accuracies in the various Higgs decay channels accessible herein.

hep-ph↗
arXiv2013

Higgs Boson in the 4DCHM: LHC phenomenology

Composite Higgs models provide an elegant solution to the hierarchy problem present in the Standard Model (SM) and give an alternative pattern leading to the mechanism of Electro-Weak Symmetry Breaking (EWSB). We present an analysis of the Higgs boson production and decay within a recently proposed realistic realization of this general idea: the 4D Composite Higgs Model (4DCHM). Comparing our results with the latest Large Hadron Collider (LHC) data we show that the 4DCHM could provide an alternative explanation with respect to the SM of the LHC results pointing to the discovery of a Higgs-like particle at 125 GeV.

hep-ph↗
arXiv2013

The 4-Dimensional Composite Higgs Model (4DCHM) and the 125 GeV Higgs-like signals at the LHC

We show that the 4-Dimensional Composite Higgs Model (4DCHM) could provide an even better explanation than the Standard Model (SM) of the current Large Hadron Collider (LHC) data pointing to the discovery of a neutral Higgs boson. The full particle spectrum of this scenario is derived without any approximation and implemented in automated computational tools to enable fast phenomenological investigation. Several benchmark sets compliant with the aforementioned data are presented and discussed.

hep-ph↗
arXiv2013

LHC physics of extra gauge bosons in the 4D Composite Higgs Model

We study the phenomenology of both the Neutral Current (NC) and Charged Current (CC) Drell-Yan (DY) processes at the Large Hadron Collider (LHC) within a 4 Dimensional realization of a Composite Higgs model with partial compositness by estimating the integrated and differential event rates and taking into account the possible impact of the extra fermions present in the spectrum. We show that, in certain regions of the parameters space, the multiple neutral resonances present in the model can be distinguishable and experimentally accessible in the invariant or transverse mass distributions.

hep-ph↗
arXiv2013

The Higgs sector of the 4DCHM after the XLVIII Rencontres de Moriond

In this proceeding, we present the current status of a $χ^2$ fit extracted from the profiling of the Higgs couplings performed at the LHC in the context of the 4-Dimensional Composite Higgs Model. Especially, we consider the data presented by the ATLAS and CMS collaborations during the XLVIII Rencontres de Moriond.

hep-ph↗
arXiv2013

A 4D Composite Higgs Model: Testing its Scalar Sector at the LHC

We explain the current Large Hadron Collider (LHC) data pointing to the discovery of a neutral Higgs boson in the context of a 4-Dimensional Composite Higgs Model (4DCHM). The full particle spectrum of this scenario is derived without any approximation and implemented in automated computational tools to enable fast phenomenological investigation. Several parameter configurations compliant with experimental constraints are presented and discussed. A $χ^2$ fit to the LHC data quantifying the consistency of the 4DCHM as a whole with experimental evidence is finally performed.

hep-ph↗
arXiv2013

Phenomenology of charged scalars in the CP-Violating Inert-Doublet Model

We study the production and decay of charged scalars, eta^\pm, in the context of a CP-Violating Inert-Doublet Model. The model is an extended version of the Inert Doublet Model with an extra Higgs doublet and provides new sources of CP violation and a dark matter candidate. As compared with the 2HDM, the particle spectrum contains two additional neutral scalars and a charged pair. These particles are subject to a Z_2 symmetry, but can be pair-produced in hadronic collisions. If a charged scalar is included in the pair, it decays to the stable dark-matter candidate (i.e., the lightest neutral inert scalar) plus Standard Model matter that consists of either two jets or a single lepton (from a virtual or real W or Z) plus missing transverse energy. Since the single production channel is available only at hadronic colliders, we consider the Large Hadron Collider environment, hence we discuss experimental perspectives and possible hallmarks of the model, such as events with a displaced vertex.

hep-ph↗
arXiv2012

Probing the charged Higgs boson at the LHC in the CP-violating type-II 2HDM

We present a phenomenological study of a CP-violating two-Higgs-doublet Model with type-II Yukawa couplings at the Large Hadron Collider (LHC). In the light of recent LHC data, we focus on the parameter space that survives the current and past experimental constraints as well as theoretical bounds on the model. Once the phenomenological scenario is set, we analyse the scope of the LHC in exploring this model through the discovery of a charged Higgs boson produced in association with a W boson, with the former decaying into the lightest neutral Higgs and a second W state, altogether yielding a b\bar b W^+W^- signature, of which we exploit the W^+W^- semileptonic decays.

hep-ph↗
arXiv2010

Higgs phenomenology in the minimal $B-L$ extension of the Standard Model at LHC

We present some phenomenology of the Higgs sector of the Minimal $B-L$ U(1) Extension of the Standard Model at the Large Hadron Collider. In this model, the existence of an extra gauge boson ($Z'$) and an extra scalar (heavy Higgs) are predicted as naturally related with the breaking of the $B-L$ (baryon minus lepton number) symmetry. For this, we have started by deriving the unitarity bounds in the high energy limit for the Minimal $B-L$ Model parameter space. This was accomplished by analysing the full class of Higgs and would-be Goldstone boson two-to-two scatterings at tree level (exploiting the Equivalence Theorem). Hence, we studied some peculiar signature that could be observed at the CERN machine in the search of both light and heavy Higgs bosons.

hep-ph↗
arXiv2010

The Z' boson of the minimal B-L model at future Linear Colliders in e+e- --> mu+mu-

We study the capabilities of future electron-positron Linear Colliders, with centre-of-mass energy at the TeV scale, in accessing the parameter space of a $Z'$ boson within the minimal $B-L$ model. We carry out a detailed comparison between the discovery regions mapped over a two-dimensional configuration space ($Z'$ mass and coupling) at the Large Hadron Collider and possible future Linear Colliders for the case of di-muon production. As known in the literature for other $Z'$ models, we confirm that leptonic machines, as compared to the CERN hadronic accelerator, display an additional potential in discovering a $Z'$ boson as well as in allowing one to study its properties at a level of precision well beyond that of any of the existing colliders.

hep-ph↗