International Journal of Modern Physics A

The results of laser spectroscopy experiments of antiprotonic helium atoms carried out at the Antiproton Decelerator of CERN, and pionic helium atoms measured at the 590MeV ring cyclotron facility of the Paul Scherrer Institute are reviewed. The former experiment determined the antiproton-to-electron mass ratio as $M_{\overline{p}}/m_e=1836.1526734(15)$. In the latter, a resonant transition $(n,\ell )=(17,16)\to (17,15)$ of pionic helium at a frequency of $\nu \approx 183760$GHz was detected. Some future perspectives are briefly described.

In this study, we examine the thermal properties of the medium formed in ultra-relativistic heavy-ion collisions at chemical freeze-out using a thermal model. We utilize experimental data on various hadron species from 0% to 5% most central Au+Au collisions at $\sqrt{s_{\mathrm{\text{NN}}}}=7.7$GeV from the STAR BES program to analyze the thermal properties, namely, chemical freeze-out temperature, baryon chemical potential, and strangeness chemical potential. We employ a ${\chi }^2$ minimization technique to obtain these thermal properties. Furthermore, we also obtain thermal properties with strangeness conservation condition and at zero potentials ${\mu }_B∕T={\mu }_S∕T=0$. We compare particle ratios from the thermal model with the experimental data. The thermal model describes particle ratios within $\pm$2.5 standard deviations and ${\chi }^2∕\mathrm{\text{NDF}}$ between 1–2. We also discuss the collision energy dependence of thermodynamic properties of the medium at freeze-out and compare results with the published STAR results and other thermal model calculations.

In the last few years, the experimental evidence of charmed mesons is increasing remarkably. In this work, we systematically studied the D meson by employing Regge phenomenology. By assuming the existence of the quasilinear Regge trajectories, several relations between Regge slope, intercept and meson masses have been extracted. With the aid of these derived relations, Regge parameters are evaluated in both the ($J,M^2$) and ($n,M^2$) planes to obtain the mass spectra of D meson. In the forthcoming years, we believe that more candidates will be reported and our predictions could provide useful information for future experimental evidences.

Significant efforts have been made in recent years to measure the properties of charmed baryons. In this work, we study the ${\mathrm{\Xi }}_c^{\prime }$ and ${\mathrm{\Omega }}_c$ baryons in the relativistic flux tube model with a quark–diquark picture of a baryon. The modified Regge relation between mass and angular momentum is used to predict the spin-average masses. The spin-dependent interactions are also included to compute the spin-dependent splitting. We calculate the masses of states belonging to the $1F$-wave and $1G$-wave of ${\mathrm{\Xi }}_c^{\prime }$ and ${\mathrm{\Omega }}_c$ baryons, which are not yet detected experimentally. Our mass predictions can offer valuable insights to experimental facilities in their search to discover the higher excited states of ${\mathrm{\Xi }}_c^{\prime }$ and ${\mathrm{\Omega }}_c$ baryons.

This contribution illustrates the four different detector technologies used in the muon spectrometer of the Compact Muon Solenoid (CMS) experiment, installed on the Large Hadron Collider (LHC), and their future upgrades. These have the aim to cope with the scheduled increase of instantaneous luminosity of the LHC in the so-called High-Luminosity LHC phase. CMS Collab. [J. Instrum. 3, S08004 (2008), https://doi.org/10.1088/1748-0221/3/08/S08004].

The search for new physics such as supersymmetry and other beyond-the-standard-model physics is a major goal of the LHC physics program. The report will cover the most recent results of supersymmetry searches using Run 2 data collected during 2016–2018 with the CMS detector at the LHC.

International Linear Collider (ILC) is a viable option for realization of a future Higgs factory. With proven accelerator technology and technically mature detector design, ILC offers well-understood physics program in the top, EW and Higgs sectors. Clean environment of electron–positron collisions, together with beam polarization of both beams and center-of-mass reach at a TeV scale, will make ILC a precision tool to probe realizations of new physics. The above will be illustrated on examples of fully simulated measurements in the Higgs sector, including Higgs couplings, Higgs self-coupling, CP violation measurements and Higgs exotic decay studies at ILC.

Nonlinear field theories often possess the so-called soliton solutions that have localized energy densities and that are characterized by topological charges n. To explore the stability of solitons with $n>1$, we consider vortices in scalar electrodynamics which is one of the rare renormalizable models that contain soliton type solutions with different topological charges. We focus on the BPS case which is particularly interesting because the quantum corrections decide on the stability of vortices with $n>1$. We also explain how to overcome technical obstacles that are encountered when computing these corrections and that arise from the singular structure of the vortex profiles.