Conveners
PD1: Theoretical Developments
- There are no conveners in this block
PD1: Theoretical Developments
- Sven Heinemeyer (CSIC (Madrid, ES))
- Roberto Franceschini (Rome 3 U.)
- Shigeki Matsumoto (Kavli IPMU)
- Jürgen Reuter (DESY Hamburg, Germany)
- Nathaniel Craig (UC Santa Barbara)
PD1: Theoretical Developments
- There are no conveners in this block
PD1: Theoretical Developments
- There are no conveners in this block
PD1: Theoretical Developments
- There are no conveners in this block
PD1: Theoretical Developments
- Nathaniel Craig (UC Santa Barbara)
- Sven Heinemeyer (CSIC (Madrid, ES))
- Roberto Franceschini (Rome 3 U.)
- Jürgen Reuter (DESY Hamburg, Germany)
- Shigeki Matsumoto (Kavli IPMU)
PD1: Theoretical Developments
- Jürgen Reuter (DESY Hamburg, Germany)
- Roberto Franceschini (Rome 3 U.)
- Nathaniel Craig (UC Santa Barbara)
- Sven Heinemeyer (CSIC (Madrid, ES))
- Shigeki Matsumoto (Kavli IPMU)
The THDMa is a new physics model that extends the scalar sector of the Standard Model by an additional doublet as well as a pseudoscalar singlet and allows for mixing between all possible scalar states. In the gauge-eigenbasis, the additional pseudoscalar serves as a portal to the dark sector, with a priori any dark matter spins states. The option where dark matter is fermionic is currently...
Extensions of the Standard Model that include vector-like quarks commonly also include additional particles that may mediate new production or decay modes. Using as example the minimal linear $\sigma$ model, that reduces to the minimal $SO(5)/SO(4)$ composite Higgs model in a specific limit, we consider the phenomenology of vector-like quarks when a scalar singlet $\sigma$ is present. This new...
We studied phenomenological implications of numerious Family Non-Universal U(1)$^\prime$ sub-models in the minimal U(1)$^\prime$ extended Supersysmmetric Model (UMSSM) possesing an extra down quark type exotic field. In doing this, we started with anomaly cancelation criteria to generate a number of solutions in which the extra U(1)' charges of the particles are treated as free parameters....
The problematic huge hierarchy between the usual 4-dimensional Planck mass scale of gravity and the ElectroWeak symmetry breaking scale can interestingly disappear at some point-like location along extra space-like dimensions where the effective gravity scale is reduced down to the TeV scale. Field theories with point-like particle locations (3-dimensional brane-worlds) or point-like...
The recent tension between local and early measurements of the Hubble constant can be explained in a particle physics context. A mechanism is presented where this tension is alleviated due to the presence of a Majoron, arising from the spontaneous breaking of Lepton Number. The lightness of the active neutrinos is consistently explained. Moreover, this mechanism is shown to be embeddable in...
In this talk, I will discuss a computational set-up for calculating the production of a massive quark-antiquark pair in $e^+e^-$ collisions at order $\alpha_s^2$ in the coupling of quantum chromodynamics (QCD) at the differential level by means of the antenna subtraction method.
Theoretical predictions on the production of top quark pairs in the continuum, and the bottom quark pairs at the...
We explore composite models with different manifestations of the Global symmetry (G) and its subgroup (H) it breaks into. One feature common to all is the possibility for the presence of one (or more) CP-odd scalar singlet states ("$\eta$") which are Goldstones of the breaking of the global symmetry. There exist possibilities where the corresponding mass corrections for the $\eta$ are highly...
Using the method of massive operator matrix elements, we calculate the subleading QED initial state radiative corrections to the process $e^+ e^− \to \gamma^∗/Z^∗$ for the first three logarithmic contributions. The calculation is performed in the limit of large center of mass energies $s \gg m_e^2$.
These terms supplement the known corrections to $O(\alpha^2)$, which were completed...
We test the assumption that fermion-loop corrections to high energy W+W− scattering are negligible when compared to the boson-loop ones. Indeed, we find that, if the couplings of the interactions deviate from their Standard Model values, fermion-loop corrections can in fact become as important or even greater than boson-loop corrections for some particular regions of the parameter space, and...
Despite the discovery of the Higgs boson with a mass of 125 GeV, the structure of the Higgs sector remains unknown. In light of the current situation that a second Higgs boson has not been discovered, indirect searches of such a new particle through observables for Higgs bosons are more and more important. This requires accurate theoretical predictions for such observables in order to compare...
In the framework of the CP conserving Two Higgs Doublet Model (2HDM), type I and II, we analyze the sensitivity to triple Higgs couplings at future high(er) energy electron-positron colliders, such as ILC and CLIC. We study the production cross section of two neutral Higgs bosons in two channels: $e^+e^-\to h_i h_j Z$ and $e^+ e^- \to h_i h_j \nu \bar{\nu}$ within several benchmark planes...
The 2HDMS is based on the CP-conserving 2HDM extended by a complex singlet
field. We impose an additional Z3 symmetry on the potential. This leads to a
Higgs-sector similar to the Next-to-Minimal Supersymmetric SM (NMSSM),
while having fewer symmetry conditions compared to supersymmetric models. We
introduce the theoretical background of this model and set it up for
phenomenological...
CMS reported a ∼ 3$\sigma$ excess at ∼ 96 GeV in the $pp\rightarrow H\rightarrow\gamma\gamma$ channel. In the same mass range, a ∼ 2$\sigma$ excess in the $e^+ e^-\rightarrow Z H, H\rightarrow b\bar{b}$ channel has been reported at LEP as well. We interpret the experimental excesses as the lightest Higgs boson in the Two-Higgs-Doublet Model with a complex singlet (2HDMS) with type II Yukawa...
The discovery of the Higgs boson has revealed that the Higgs quartic coupling becomes small at very high energy scales. Guided by this observation, we introduce Higgs Parity, which is a spontaneously broken symmetry exchanging the standard model Higgs with its parity partner. In addition to explaining the small Higgs quartic coupling, Higgs Parity can provide a dark matter candidate, solve the...
We present two new extractions of the QCD coupling constant at the Z pole, $\alpha_S(m_Z)$, from detailed comparisons of inclusive W and Z hadronic decays data to state-of-the-art perturbative Quantum Chromodynamics calculations at next-to-next-to-next-to-leading order (N$^{3}$LO) accuracy, incorporating the latest experimental and theoretical developments. In the W boson case, the total width...
In this talk I will describe our recent work on N$^3$LL+NNLO resummed prediction for 2-jettiness differential distribution for boosted $t\bar t$ pairs produced in $e^+e^-$ collisions calculated in the framework of SCET+(boosted) HQET. The prediction incorporates a precise short distance top mass scheme, such as the MSR scheme. Renormalon subtractions in the mass and soft function play a key...
Precision studies of the Higgs boson at future $e^+e^-$ colliders can help to
shed light on fundamental questions related to electroweak symmetry breaking,
baryogenesis, the hierarchy problem, and dark matter.
The main production process, $e^+e^- \to HZ$, will need to be controlled with
sub-percent precision, which requires the inclusion of next-to-next-to-leading
order electroweak (NNLO)...
We discuss a possibility that the parameter space of the two Higgs doublet model is significantly narrowed down by considering the synergy between direct searches for additional Higgs bosons at the (HL-)LHC and precision measurements of the Higgs boson properties at future e+e- colliders such as the International Linear Collider (ILC). We show that, in the case where the coupling constants of...
We propose to utilize angularity distributions in Higgs boson decay to probe light quark Yukawa couplings at $e^+e^-$ colliders. Angularities $\tau_a$ are a class of 2-jet event shapes with variable and tunable sensitivity to the distribution of radiation in hadronic jets in the final state. Using soft-collinear effective theory (SCET), we present a prediction of angularity distributions...
In this talk, I discuss the phenomenology of a minimal model for GeV-scale Majorana dark matter (DM) coupled to the standard model lepton sector via a charged scalar singlet. The theoretical framework extends the Standard Model by two $SU(2)_L$ singlets: one charged Higgs boson and a singlet right-handed fermion. The latter plays the role of the DM candidate. We show that there is an...
The leptophilic weakly interacting massive particle (WIMP) is realized in a minimal renormalizable model scenario where scalar mediators with lepton number establish the WIMP interaction with the standard model (SM) leptons. We perform a comprehensive analysis for such a WIMP scenario for two distinct cases with an SU(2) doublet or singlet mediator considering all the relevant theoretical,...
In this talk we will discuss about a general anomaly free U(1) extension of the Standard Model which describes a small neutrino mass after the seesaw mechanism. In this scenario a new force carrier called 𝑍′ Can be introduced which plays an interesting role to study a variety of phenomenological aspects including forward backward asymmetry, left right asymmetry, Higgs physics and dark matter...
In gauge-Higgs unification (GHU), the 4D Higgs boson appears as a part of the fifth dimensional component of 5D gauge field. Recently, an $SO(11)$ GUT inspired $SO(5)\times U(1)\times SU(3)$ GHU model in has been proposed. In the GHU, Kaluza-Klein (KK) excited states of neutral vector bosons, photon, $Z$ boson and $Z_R$ boson, appear as neutral massive vector bosons $Z'$s. The $Z'$ bosons in...
The Higgs trilinear coupling can serve as a unique probe to investigate the structure of the Higgs sector and the nature of the electroweak phase transition, and to search for indirect signs of New Physics. At the same time, classical scale invariance (CSI) is an attractive concept for BSM model building, explaining the apparent alignment of the Higgs sector and potentially relating to the...
A light pseudoscalar in extended Higgs sector provides solution to muon anomalous magnetic moment and/or dark matter. We explore the prospect of Yukawa production of such a light boson which can exist in an extended Higgs sector like 2HDM. Considering ILC "Higgs factory" with CM Energy of 250 GeV, we show that the available parameter space can be examined by the (tau) Yukawa process at 5 sigma...
We study the scenario of the two Higgs doublet model, where the Higgs potential respects the twisted custodial symmetry at high energy scale. In this scenario, experimental data for the Higgs boson couplings and those for the electroweak precision observables can be explained even when the masses of the extra Higgs bosons are near the electroweak scale. We also discuss the predictions on the...
I discuss how to employ collinear factorisation theorems for the computation of generic hard-production processes at e+e- colliders, in particular by stressing the strong analogies with their analogues which are routinely used in the context of LHC physics. I shall briefly describe some recent work on the universal behaviour associated with small-angle emissions in QED, that leads to the...
Applications of Quantum Chromodynamics to collider phenomenology largely rely on factorization, the separation of universal low-energy dynamics from perturbative high-energy physics. Factorization of cross sections was originally established at the leading power in an expansion in the ratio of these energies, but in view of precision physics subleading terms become relevant. I will present...
WHIZARD is a multi-purpose Monte Carlo event generator very well suited for the simluation of lepton collider physics.
In this talk, we are reporting on the recent theoretical and technical developments with respect to the implementation of next-to-leading-order perturbative corrections and the UFO interface to use models beyond the Standard Model within WHIZARD.
