Présidents de session
Parallel session 3: BSM phenomenology
- Benjamin Fuks
Parallel session 3: BSM phenomenology
- Pietro Slavich (LPTHE-Jussieu)
Parallel session 3: BSM phenomenology
- Michelle Frigerio
Parallel session 3: BSM phenomenology
- Keisuke Harigaya
Parallel session 3: BSM phenomenology
- Marcin Badziak
Parallel session 3: BSM phenomenology
- Aldo Deandrea
In the Standard Model, CP violation in the Electroweak sector is parametrized by the Jarlskog Invariant. This is the order parameter of CP-violation, in the sense that it vanishes iff CP is conserved. When higher dimensional operators are allowed, and the Standard Model Effective Field Theory is constructed, numerous new sources for CP violation can appear. However, the description of CP...
We present a basis of dimension-eight Green’s functions involving Standard Model (SM) bosonic fields, consisting of 86 new operators. Rather than using algebraic identities and integration by parts, we prove the independence of these interactions in momentum space, including a discussion on evanescent bosonic operators.
Our results pave the way for renormalising the SM effective field theory...
Effective field theories (EFTs) are a powerful tool for the exploration
of potential new physics in a model-independent way. At a time when
there is a lack of clarity on how to extend the Standard Model, the
Standard Model effective field theory (SMEFT) and related EFTs have been
receiving an increasing amount of attention. For example, the number of
SMEFT operators, up to high mass...
The unaddressed origin of Electroweak Symmetry Breaking (EWSB) in the Standard Model (SM) motivates a closer inspection of the Higgs EW couplings. In models such as the composite Higgs, the Higgs couplings are generated by the interactions with a new heavier sector that triggers EWSB. These couplings of the Higgs have an associated momentum dependence that can be parameterized by form factors....
We develop methods to study the scalar sector of multi-Higgs models with large discrete symmetry groups that are softly broken. While in the exact symmetry limit, the model has very few parameters and can be studied analytically, proliferation of quadratic couplings in the most general softly broken case makes the analysis cumbersome. We identify two sets of soft breaking terms which play...
It is remarkable that the matter fields in the Standard Model (SM)
are apparently unified into the SU(5) representations.
A straightforward explanation of this fact is to embed all the SM gauge group into a simple group containing SU(5).
Recently, however, a new framework ``fake GUT" has been proposed.
In this new framework,
the apparent matter unification can be explained by a chiral...
In this proposed talk, we present a gauge-Higgs grand unification setup that employs 5D warped space with a SU(6) bulk gauge field that includes both a SU(5) grand unified theory (GUT) and a Higgs sector as a scalar component of the 5D vector field, solving the hierarchy problem. By appropriately breaking the gauge symmetry on the boundaries of the extra dimension the issue of light exotic new...
A strongly-coupled gauge theory with a large number of colours can be conveniently studied using holography. We focus on composite fermionic operators in the limit of a large number of flavours, suitable to realise partial compositeness of the Standard Model fermions. We compute the fermion mass spectrum holographically, and identify regions in parameter space where a composite fermion can...
We discuss a new paradigm, where gauge couplings do not need to be equal at any give scale, instead they run towards the same fixed point in the deep ultraviolet. We provide a concrete example based on SU(5) with one compact extra space dimension. By construction, fermions are embedded in different SU(5) bulk fields, hence baryon number is conserved and proton decay is forbidden. The lightest...
Among the simplest new physics explanations of the muon g-2 anomaly are scenarios with chirally enhanced contributions. The new particles can be very heavy, even beyond the reach of future colliders, and thus the confirmation of such explanations might rely only on indirect evidence. I will discuss that these models generically predict correlations with related signatures that include possible...
The 4.2𝜎 discrepancy between the theoretical prediction for the muon g-2 and the experimental results is accompanied by other anomalies. Determinations of the hadronic cross section from KLOE and BaBar, a crucial input for the data-driven prediction, disagree by almost 3 𝜎. Furthermore, the data-driven result disagrees with the most precise lattice determination by 2.1 𝜎. In this talk I will...
The observed value of the muon magnetic dipole moment can be explained in models with weakly-interacting massive particles (WIMPs) coupled to muons. However, a considerable range of parameter space of such models will remain unexplored in future LHC experiments and dark matter (DM) direct searches. Here I will discuss the temperature observation of neutron stars (NSs) as a promising way to...
In this work we discuss that vector-like quarks in the fundamental or higher-dimensional representation of QCD generally break chiral symmetry by dynamically generated condensates. The numerical solution of the Dyson-Schwinger equation shows that this can generate considerable scales, because the vacuum expectation value of the condensate increases with the hard vector-like mass. Transferring...
Motivated by addressing the hierarchy problem via the conformal standard model (cSM), we present a general formalism to analyze the generation of non-trivial minima in the one-loop effective potential using a set of exact criticality equations which, in analogy to the Nambu-Jona-Lasinio model, may be understood as gap-equations. Given the intuitive nature of these equations, we are able to...
Fundamental unsolved questions urge us to find the way beyond the SM. Among them, the problems of “Naturalness” and “Hierarchy”. Several popular attempts towards the solution have been put forward, including scale invariant BSM models, where it is assumed that dimensional regularization is endowed with special physical properties. In this talk, these attempts will be carefully confronted with...
Diboson production processes constitute an interesting probe of New Physics related to the Higgs boson and the EW sector. We revisit the 𝑊ℎ and 𝑍ℎ production processes, with ℎ→𝑏𝑏¯ and leptonically decaying gauge bosons. For the first time, we include the neutrino decay channel of the Z boson and perform a scale-invariant b-tagging. We study these processes in the SMEFT framework and derive...
In recent years more attention was attracted by studies on long-lived charged particles predicted
by some of BSM scenarios. We present a highly model independent study targeting colour-singlet
and colour-triplet particles, with electric charges up to 8 times the elementary charge. In our work,
we assess the possibility to detect such particles during Run-3 and at HL-LHC, by estimating...
One of the most promising methods to search for axions is a light-shining-through-walls (LSW) experiment. In this talk, I will discuss the possibility of performing an LSW experiment at the ILC experiment, where photon beams are generated for positron production. The photon beam is energetic and intense; the energy is of order MeV and the number of photons is about 1024 per year. Due to the...
We explore a common symmetrical origin for two long standing problems in particle physics: the strong CP and the fermion mass hierarchy problems. The Peccei-Quinn mechanism solves the former one with an anomalous global 𝑈(1)𝑃𝑄 symmetry. Here we investigate how this 𝑈(1)𝑃𝑄 could at the same time explain the fermion mass hierarchy. We work in the context of a four-Higgs-doublet model which...
Martinus Veltman was the first to point out the inconsistency of the experimental value for the decay rate of \pi^0\rightarrow\gamma\gammaπ
0
→γγ and its calculation by J. Steinberger with the very successful concept of the pion as the (pseudo)Nambu-Goldstone boson of the spontaneously broken global axial symmetry of strong interactions. That inconsistency has been resolved by J. Bell and...
