A summary of CMS searches for new neutral resonances with the main focus on scalars and pseudoscalars, based on data collected during Run 2 of the LHC is presented. Special emphasis is given to the most recent results. Abstract Published by the Jagiellonian University 2025 authors

Recent theoretical results renewed the interest in charged-particle multiplicity distributions. The Shannon entropy of such distributions is conjectured to be related to the entanglement or von Neumann entropy of the partonic quantum system. In this paper, we show that the measured charged-particle multiplicities can be derived from the principle of maximum entropy (POME or MAXENT) without any <span class="it">a priori</span> physical assumption. The approach provides a natural explanation for the well-known negative binomial shape of the measured distributions. Abstract Published by the Jagiellonian University 2025 authors

Quantum electrodynamics mechanisms can be used to analyse the proton structure, with particular attention paid to its radius. The cross section for the \(\gamma \gamma \to \ell ^+\ell ^-\) process is placed in the context of proton–proton collisions, allowing for the study of effects related to the distribution of the electromagnetic field around the proton. This research compares the theoretical results with the data from the ATLAS and CMS experiments at the LHC. It allows for the verification of the approach used and the determination of possible model constraints. Abstract Published by the Jagiellonian University 2025 authors

Processes with scattered protons present in the final state, hereafter called forward physics, are briefly described. ATLAS sub-detectors, ALFA and AFP, dedicated to measure scattered protons, are shown. A few analyses using data collected by these detectors are presented. Namely, elastic scattering at \(\sqrt {s} = 7\), 8, and 13 TeV, exclusive di-pion and di-lepton production, and a search for the axion-like particles. Abstract Published by the Jagiellonian University 2025 authors

Small violations of CPT symmetry are permissible in several extensions of the Standard Model. Recently, we published new constraints on the CPT violation parameter \(z\) by reinterpreting the LHCb measurement of the time-dependent asymmetry in the Cabbibo-favoured \(D^0 \rightarrow K^{-}\pi ^{+}\) and \(\bar {D}^{0} \rightarrow K^{+}\pi ^{-}\) decays. The resulting limits are two orders of magnitude stricter than the previous leading result reported by the FOCUS Collaboration. In this contribution, we discuss the recent result, which is the tightest constraint on the CPTV in the charm sector to date. We also explore prospects for placing bounds on CPT violation in the Standard Model Extension framework. Abstract Published by the Jagiellonian University 2025 authors

The AFP global alignment method using photon-fusion-induced lepton pair production is discussed. The alignment corrections are derived from a comparison of the expected proton positions to the measured ones. Results obtained with di-muon events are verified with di-electron events. Abstract Published by the Jagiellonian University 2025 authors

The Precision Proton Spectrometer is a subdetector of the CMS experiment at the LHC used for detecting forward protons. It comprises tracking and timing detectors located around 220 meters from the CMS detector, along the LHC beam pipe, on both sides. Due to their challenging operating environment, they require frequent calibration. Procedures for performing these calibrations have already been developed in LHC Run 2 (2015–2018), but in Run 3 (2022–2026), the timing detector calibration algorithm has been shown not to perform ideally for most of the data-taking runs due to data anomalies and irregularities. Moreover, calibrating so many runs every year is a tedious task. As a result, an in-house parallel processing automation framework has been developed to perform the calibration and validate its results. In the paper, an improved timing calibration algorithm was shown, as well as anomalies and irregularities that were observed and corrected using it. Abstract Published by the Jagiellonian University 2025 authors

Some of the outstanding issues of the Standard Model (SM) can be solved with an extension of its scalar sector. We discuss SM extensions to tackle matter–antimatter asymmetry, the shape of the Higgs potential, and dark matter. The amount of CP-violation in the SM is not sufficient for baryogenesis and, therefore, new sources of CP-violation are needed. Searches for CP-violation are one of the top priorities of the future LHC runs. Also, the still unknown shape of the Higgs potential can be probed in di-Higgs final states at the LHC. Finally, extensions of the SM can provide dark matter candidates which can be probed at the LHC in events with a large amount of missing energy, together with one or more SM particles. Abstract Published by the Jagiellonian University 2025 authors

With the LHC full Run 2 \(pp\) collision dataset collected at 13 TeV, very precise measurements of Higgs boson properties and its interactions can be performed, shedding light on the electroweak symmetry-breaking mechanism. This contribution presents measurements performed using the Run 2 dataset, as well as first results using the Run 3 \(pp\) collision dataset collected since 2022 at 13.6 TeV. Measurements of the Higgs boson properties by the ATLAS experiment in various decay channels are shown, including its production cross sections, simplified template cross sections, mass, width, differential and fiducial cross sections, as well as their combination and interpretations. Specific scenarios of physics beyond the Standard Model are tested, as well as a generic extension in the framework of the Standard Model Effective Field Theory. The paper also presents the latest \(HH\) searches, which are sensitive to the Higgs boson self-coupling. Results are shown in terms of sensitivity to the SM \(HH\) production and limits on the Higgs boson self-coupling. Abstract Published by the Jagiellonian University 2025 authors

The quantum interference effects have been studied across many collision systems with a wide spectrum of energies and particle species. They were the subject of studies in many experiments using different accelerators. Studying the quantum correlations may provide essential information to understand the mechanism of hadronization, describing in particular the space-time structure of the hadronization source. As the measured correlation parameters depend on various observables, such as charged particle multiplicity, transverse momentum, or hadron mass, it is essential to model the observed trends properly. In particular, it was observed that the correlation radii become smaller with an increasing mass of the studied hadron species, which was a conclusion driven mainly by the LEP measurements performed for a number of different types of hadrons. One of the approaches aiming at interpretation of the observed dependence of the correlation radius on the hadron mass is the quantum-mechanical model employing the Björken–Gottfried condition, suggesting the universality of the source radius, which is independent of the hadron mass. Abstract Published by the Jagiellonian University 2025 authors

The CMS experiment has delivered numerous significant measurements using data from LHC Run 2 and the ongoing Run 3. This report explains key components of the CMS detector relevant to heavy-flavour physics. The short introduction to CP violation in \(B_s\rightarrow J/\psi \phi (1020)\) is given, followed by the recent CMS results, confirming the CP violation in this channel. The search for CP violation in \(D_s\rightarrow K_\mathrm {S}^0 K_\mathrm {S}^0\) channel is presented. In addition, the most important information on selected recent CMS heavy-flavour physics results is highlighted. It includes: measurement of \(B_s\rightarrow J/\psi K_\mathrm {S}\) effective lifetime, test of lepton flavour universality with \(R_{J/\psi }\), and search for rare decays in \(D^0\rightarrow \mu ^+\mu ^-\). Finally, the CMS measurements of \(B/B_s\rightarrow \mu ^+\mu ^-\) are reminded. Abstract Published by the Jagiellonian University 2025 authors

The ALICE experiment has significantly upgraded its detectors, enabling new measurements in ultra peripheral collisions of lead nuclei with an integrated luminosity of \(\mathcal {L} = 7\)/nb and 6/nb during Run 3 and Run 4, respectively. Investigation of light-by-light scattering in the low diphoton invariant mass is studied in this paper. The predictions presented here take into account the acceptance of the current EMCal and PHOS electromagnetic calorimeters, TPC and ITS tracking devices in the central barrel, as well as the future Forward Calorimeter, FoCal. Results from the <span class="sf">SuperChic</span> and <span class="sf">UPCgen</span> Monte Carlo generators are compared across all possible reconstruction topologies. Abstract Published by the Jagiellonian University 2025 authors

Neutrinos are mysterious elementary particles due to their tiny masses, electrical neutrality, and interaction only through gravitational and weak force, which makes their detection challenging. Their astrophysical origins and the production mechanism remain unclear. This contribution will presents the prospect of the acoustic simulation to detect ultra-high-energy (UHE) neutrinos with KM3NeT. KM3NeT, the Cubic Kilometer Neutrino Telescope located in the Mediterranean Sea, is equipped with state-of-the-art hydrophones and digital optical modules. To investigate the high-energy astrophysical origins of neutrinos, a study of tidally disrupted events as potential candidates is proposed. Abstract Published by the Jagiellonian University 2025 authors

This contribution provides an overview of the Large Hadron Collider operation during Run 3, highlighting key achievements and challenges encountered. A detailed account of major LHC events and results in 2023 and 2024 is presented, including notable milestones in machine operation, luminosity evolution, and beam performance for protons and ions. Additionally, prospects for LHC operations in 2025 and 2026 are discussed, outlining planned improvements and expected operational scenarios. Finally, the status of the High-Luminosity LHC preparation is reviewed, focusing on key upgrades, infrastructure developments, and current schedule. Abstract Published by the Jagiellonian University 2025 authors

The extensive top-quark samples collected by the ATLAS experiment at the LHC have enabled precise measurements of the top-quark production cross section, reaching unprecedented accuracy and extending into previously unexplored kinematic regimes. These datasets have also provided new insights into top-quark properties, facilitated the observation of rare production processes predicted by the Standard Model, and led to significant advancements in searches within the top-quark sector. This contribution presents key highlights from the ATLAS top-quark physics program, showcasing the latest measurements and emphasizing the sector’s broad scientific potential. Abstract Published by the Jagiellonian University 2025 authors

The LHCb experiment at CERN’s Large Hadron Collider is dedicated to studying heavy-flavour physics, particularly the decays and properties of beauty and charm hadrons, to explore CP violation and phenomena beyond the Standard Model. This contribution presents a selection of recent measurements in rare decays and CP violation. Abstract Published by the Jagiellonian University 2025 authors

Lepton Flavor Violation (LFV) in the neutral lepton sector (neutrino oscillation mechanism) compels us to check for LFV in other physics processes to hunt for any New Physics (NP) signatures. LFV \(B\)-meson decays \(B\rightarrow K \tau \ell \) (\(\ell = e,\mu \)) are one such example, which in some NP scenarios are within the reach of current experimental sensitivity. We are searching for them in Belle, which provides a clean environment to study such processes. Using the boosted decision tree approach, we have significantly suppressed the background. Validation of the analysis approach is performed on two different control modes, and we have found reasonable agreement between the Belle data and Monte Carlo (MC). Abstract Published by the Jagiellonian University 2025 authors

This report summarises measurements of the Higgs boson properties performed with the CMS experiment at the CERN LHC. The measurements presented here base on data from \(pp\) collisions at the center-of-mass energy of 7, 8, and 13 TeV collected up to the year 2018 and corresponding to integrated luminosity of 5, 20, and 138 fb\(^{-1}\), respectively. These results represent the most up-to-date knowledge on the Higgs boson properties. All presented measurements agree with predictions of the Standard Model of particle physics within their uncertainties. Abstract Published by the Jagiellonian University 2025 authors

The ATLAS experiment at the Large Hadron Collider continues to deliver high-precision measurements that probe the electroweak sector of the Standard Model. This summary highlights recent results using proton–proton collision data, including precision determinations of the \(W\)-boson mass and width, measurements of exclusive hadronic \(W\) decays, and studies of \(W\)- and \(Z\)-boson production. New insights into the electroweak gauge structure through studies of diboson polarization, radiation amplitude zero effects, and rare quartic gauge couplings are also reviewed. These results offer stringent tests of the Standard Model and increase sensitivity to potential New Physics. Abstract Published by the Jagiellonian University 2025 authors

We discuss the production of \(D\) mesons and \(J/\psi \) quarkonia in proton–nucleus collisions in the fixed-target LHCb experiment. We consider gluon–gluon fusion within \(k_{\mathrm {t}}\)-factorization, processes initiated by intrinsic charm in the nucleon and perturbative recombination mechanism. All the mechanisms seem to be necessary to describe the LHCb experimental data. We get an upper limit for the probability of the large-\(x\) \(c \bar c\) Fock component in the nucleon, which is slightly less than 1%. The recombination mechanism allows for the description of \(D^0\) and \(\bar D^0\) asymmetry observed by the LHCb Collaboration. We also discuss the production of \(J/\psi \) quarkonia, including colour singlet mechanisms. We include \(g^* g^* \to J/\psi g\) and \(g^* g^* \to \chi _c(1^+,2^+)(\to J/\psi \gamma )\) within \(k_{\mathrm {t}}\)-factorization approach. Different unintegrated gluon distributions from the literature are used. A reasonable agreement is achieved with some gluon distributions from the literature. Abstract Published by the Jagiellonian University 2025 authors