Legacy Run 2 measurements of the Higgs cross-section in tautau and other final stateswith ATLAS (24+6)

• Ximo Poveda (IFIC (CSIC-UV))

Room: 1001-Primera-1-1-1 - Paterna. Seminario The IFIC ATLAS group has been one of the main contributors to the recently released results of the Higgs boson measurements in the H->tautau channel using the Run-2 dataset (arXiv:2407.16320). This new analysis includes a significant extension of the measurements in the Simplified Template Cross-Section (STXS) framework for VBF and ttH production. Furthermore, the first ATLAS H->tautau unfolded fiducial differential measurement is performed in the VBF phase space, whose results are interpreted within the SMEFT framework. THis result will be discussed along with other ATLAS cross-section measurements

VBFNLO 3.0 Release (24+6)

• Iván Rosario

Room: 1001-Primera-1-1-1 - Paterna. Seminario We present the latest release of VBFNLO, a parton-level Monte Carlo generator. This update introduces several key enhancements: parallel processing capabilities through MPI, additional physics processes, unitarization procedures for Effective Field Theories (EFTs), three new dimension-8 operators, and implementation of the Binoth Les Houches Accord (BLHA) interface for integration with event generators such as Herwig. VBFNLO continues to serve as a valuable tool for LHC experimental collaborations, offering both verification capabilities for modern automatic Monte Carlo generators and superior computational efficiency in many processes. In the context of Higgs physics, we demonstrate new results for Vector Boson Scattering (VBS) processes Hjj and Hjjj at NLO QCD accuracy matched to parton showers, and analyze their comparison with fixed-order calculations.

Probing Gauge-Higgs Unification models at the ILC with quark-antiquark forward-backward asymmetry at center-of-mass energies above the $Z$ mass (12+3)

• Jesús Pedro Márquez Hernández

Room: 1001-Primera-1-1-1 - Paterna. Seminario The International Linear Collider (ILC) will allow the precise study of $e^{+}e^{-}\rightarrow q\bar{q}$ interactions at different center-of-mass energies from the $Z$-pole to 1 TeV. In this paper, we discuss the experimental prospects for measuring differential observables in $e^{+}e^{-}\rightarrow b\bar{b}$ and $e^{+}e^{-}\rightarrow c\bar{c}$ at the ILC baseline energies, 250 and 500 GeV. The study is based on full simulation and reconstruction of the International Large Detector (ILD) concept. Two gauge-Higgs unification models predicting new high-mass resonances beyond the Standard Model are discussed. These models predict sizable deviations of the forward-backward observables at the ILC running above the $Z$ mass and with longitudinally polarized electron and positron beams. The ability of the ILC to probe these models via high-precision measurements of the forward-backward asymmetry is discussed. Alternative scenarios at other energies and beam polarization schemes are also discussed, extrapolating the estimated uncertainties from the two baseline scenarios.

Bounds on top operators in the SMEFT from recent LHC measurements (24+6)

• Maria Moreno Llácer (IFIC (CSIC-UV), Valencia)

Room: 1001-Primera-1-1-1 - Paterna. Seminario The recent measurements of the Large Hadron Collider and legacy results from previous colliders allow to probe the couplings of the top quark in the context of Effective Field Theories (EFT), such as the Standard Model EFT (SMEFT). We present the results of a global SMEFT fit including those recent experimental results. We show that LHC Run 2 data allow, for the first time, to overconstrain the two-fermion and $qqt\bar{t}$ four-fermion operator coefficients and yields competitive bounds. We compare the current bounds to projections for the HL-LHC and future lepton colliders, that can yield powerful constraints.

Light states in real multi-Higgs models with spontaneous CP violation (24+6)

• Miguel Nebot (U. of Valencia - IFIC)

Room: 1001-Primera-1-1-1 - Paterna. Seminario In models with extended scalar sectors consisting of multiple Higgs doublets that trigger spontaneous electroweak symmetry breaking, it might be expected that the abundance of dimensionful quadratic couplings in the scalar potential could allow for a regime where, apart from the would-be Goldstone bosons and a neutral Higgs-like state, all new scalars have masses much larger than the electroweak scale. In the case of models where CP invariance holds at the lagrangian level but is broken by the vacuum, we show that such a reasonable expectation does not hold. When perturbativity requirements are placed on the dimensionless quartic couplings, the spectrum of the new scalars includes one charged and two additional neutral states whose masses cannot be much larger than the electroweak scale

ATLAS Run 2 non resonant HH measurements of Higgs Boson Self-Coupling, combinations and projections for HL-LHC (24+6)

• Francesco Curcio (IFIC, U. Valencia - CSIC)

Room: 1001-Primera-1-1-1 - Paterna. Seminario A combination of searches for non-resonant Higgs boson pair production in the $b\bar{b}b\bar{b}$, $b\bar{b}\gamma\gamma$, $b\bar{b}\tau^{+}\tau^{-}$ final states with the ATLAS detector provides constraints on the Standard Model prediction. Current analyses at $\sqrt{s} = 13 \, \text{TeV}$ with 126–140 $\text{fb}^{-1}$ of data set a 95% CL upper limit of 2.9 times the Standard Model prediction on the Higgs boson pair production rate, with an expected limit of 2.4 under no pair production.

Offline electron identification using a Deep Neural Network (12+3)

• Enrique Valiente Moreno (CSIC-IFIC (UV))

Room: 1001-Primera-1-1-1 - Paterna. Seminario Previously in ATLAS a likelihood approach has been used for prompt electron identification against different possible backgrounds. Over the last few years, great efforts have been made in order to develop a versatile, powerful and reliable deep neural network (DNN) that is able to perform a multinomial classification of electrons according to different pre-defined classes. Once this machine learning algorithm learns the fundamental characteristics of each electron type, different discriminants can be built out of the multinomial scores given by the DNN in order to decide to decide whether an electron can be identifed as prompt within a pre-defined efficiency.

Aligned Two Higgs Doublet Model and electric dipole moment of electron (24+6)

• Anirban Karan

Room: 1001-Primera-1-1-1 - Paterna. Seminario Electric dipole moment of electron (eEDM) is an interesting observable to search for new sources of CP violation and hence for prospect of BSM scenarios. In the SM, eEDM starts getting contributions from four-loop order, and thus it posses an extremely tiny value of $d_e^{SM}\leq 10^{-38}e\,cm$. However, the current experimental bound on eEDM is $d_e^{exp}\leq 10^{-30} e\,cm$ which leaves a large room for the BSM scenarios to be condidered. Aligned two Higgs doublet model (A2HDM) is a simplest extension of the SM. It can provide CP violation in both scalar and Yukawa sector resulting in a larger value of eEDM. We have studied the full two-loop contribution to eEDM in this model. We reproduce the same leading log behaviour from the EFT approach too.

Running constants: experimental evidence for the scale evolution of the strong coupling and quark masssesle evolution of the strong coupling and quark massses (24+6)

• Marcel Vos (IFIC Valencia)

Room: 1001-Primera-1-1-1 - Paterna. Seminario This review presents the current experimental evidence for the scale dependence of the parameters of the QCD Lagrangian. Ample evidence over a broad range of energy scales exists for the running of the strong coupling. I will review studies into the scale evolution of quark masses in more detail, with particular emphasis on the bottom quark, where Higgs data has helped to raise evidence for "running" of the mass to a significance greater than 5 sigma. I will discuss ongoing studies beyond the current state of the art and will present new directions and prospects at existing and future facilities. This is meant to be a proper review, but leans heavily on IFIC contributions in PRL128 (2022) 12, J.Phys.G 51 (2024) 9, and Snowmass reports arXiv:2203.16994, arXiv:2209.11267

Pushing the boundaries of perturbative QCD (and more...) for LHC physics (24+6)

• Leandro Javier Cieri (Universidad de Valencia - IFIC)

Room: 1001-Primera-1-1-1 - Paterna. Seminario The Large Hadron Collider (LHC) is currently in its third and final run, exceeding its design luminosity and producing an unprecedented amount of high-precision data. The remarkable accuracy of these measurements demands equally precise theoretical predictions to fully exploit the LHC's potential for new discoveries and precise characterization of the Standard Model. The pursuit of percent-level or even sub-percent-level theoretical accuracy necessitates advancements in theoretical calculations, particularly in perturbative Quantum Chromodynamics (QCD). The talk will delve into the current state-of-the-art in theoretical calculations for LHC phenomenology, highlighting recent breakthroughs in next-to-next-to-leading order (NNLO) and ongoing efforts to push the boundaries towards N3LO precision. The challenges and future directions in achieving the required theoretical accuracy for the LHC's high-precision era and future colliders will also be discussed.

Extraction of the top quark pole mass from differential cross sections (12+3)

• Luis Monsonis Romero (CSIC)

Room: 1001-Primera-1-1-1 - Paterna. Seminario We present a measurement of the top quark pole mass, based on a method developed at IFIC where the mass is determined from the normalized differential cross section for associated production of a top quark pair with an energetic jet. The new result is based on the di-lepton channel, using 140/fb of pp collision data at sqrt(s) = 13 TeV, collected by the ATLAS experiment in run 2 of the Large Hadron Collider. The top quark pole mass is extracted by comparing the measured differential cross section to fixed-order predictions for the pp -> ttbar + jet process and the 2->7 process that includes top quark decay and non-resonant contributions. The measurement reaches a precision below 1 GeV, making it the most precise ATLAS top quark pole mass determination to date. The analysis was approved by the top group on the 7th of November and will be unblinded in the next weeks. It can be presented as "work in progress" at our meeting.

IFIC Seminar on next generation of QCD parton showers Room: 1001-Primera-1-1-1 - Paterna. Seminario