Proton decay has been studied for decades now as one of the consequences of grand unified theories. Among those theories exists SU(5) theory, firstly postulated by H. Georgi and S. Glashow [1]. However, there were some problems with this theory such as mass degeneration and coupling unification [1-3]. This created a need for an extension of an original SU(5) model – a specific minimal SU(5) [4-5]. In this minimal SU(5) there is a viable parameter space with achievable gauge coupling unification. In this article, we present the process of gauge coupling unification for three mass scales of new physics states in this model, namely for 1 TeV, 10 TeV, and 100 TeV.

We assess proton decay signatures in the simplest viable $SU(5)$ model with regard to constraints on parameters governing the Standard Model fermion mass spectrum. Experimental signals for all eight two-body proton decay processes result from exchange of two gauge bosons, a single scalar leptoquark, or their combination. Consequently, it enables us to delve into an in-depth anatomy of proton decay modes and anticipate future signatures. Our findings dictate that observing a proton decay into $p\to\pi^0e^+$ indicates gauge boson mediation, with the potential for observation of $p\to\eta^0e^+$ mode. Alternatively, if decay is through $p\to K^+\overline\nu$ process, it is mediated by a scalar leptoquark, possibly allowing the observation of $p\to\pi^0\mu^+$. Detection of both $p\to\pi^0 e^+$ and $p\to K^+\overline\nu$ could enhance $p\to\pi^0\mu^+$ through constructive interference. The model predicts inaccessibility of $p\to\pi^+\overline\nu$, $p\to\eta^0\mu^+$, $p\to K^0e^+$, and $p\to K^0\mu^+$, regardless of the dominant mediation type, in the coming decades. In summary, through a comprehensive analysis of proton decay signals, gauge coupling unification, and fermion masses and mixing, we precisely constrain the parameter space of the $SU(5)$ model in question.

We discuss the scope of accreditation presentation in certificates and annexes issued by NABs for calibration laboratories (accredited in accordance with ISO/IEC 17025 [1]) in accordance with ILAC P14:2020 [2], with specific requirements stated in clause 4.3 for expression of measurement uncertainty (expanded uncertainty) regarding the unit. Due to the close link between accreditation, metrology, and standardization, we consult BIPM documents [3] and discuss the practice in metrological institutes when it comes to expressions of expanded uncertainty in order to give another view and arguments on ILAC P14:2020 requirement for expanded uncertainty to be expressed only in terms of measurand's unit. We present our case for the quantity of temperature, in addition to some other physical quantities with similar cases as temperature.

We present different approach in teaching physics for high-school students for various branches of physics, such as thermodynamics, electromagnetism, etc. When we use term “different”, we want to offer complementary approach to the traditional one. This approach involves bringing everyday situations [1], such as drinking tea in a desert, making coffee, etc., to the physics classroom context without theoretical teaching with formulae, laws, and definitions in the beginning or opening of the class. The idea is to develop logical concepts to prepare students for theoretical teaching and introduce formulae to them in order to have a complete frame of specific physical phenomena. Some classes include practical demonstrations [2] where students immerse in discussion and spontaneously involve in growing logical concepts needed for better adoption of definitions, laws, and formulae [3].

We present phenomenological study of the most minimal realistic SU(5) model that owns its predictivity solely to the gauge symmetry and the representational content. The model is built entirely out of the fields residing in the first five lowest dimensional representations that transform non-trivially under the SU(5) gauge group. It has eighteen real parameters and fourteen phases, all in all, to address experimental observables of the Standard Model fermions and accomplishes that via simultaneous use of three different mass generation mechanisms. Furthermore, it inextricably links the origin of the neutrino mass to the experimentally observed difference between the down-type quark and charged lepton masses. The main predictions of the model are that (i) the neutrinos are Majorana particles, (ii) one neutrino is massless, (iii) the neutrinos have normal mass ordering, and (iv) there are four new scalar multiplets at or below a 120TeV mass scale. A one-loop analysis demonstrates that an improvement of the current p→ πe partial lifetime limit by a factor of 2, 15, and 96 would require these four scalar multiplets to reside at or below the 100TeV, 10TeV, and 1TeV mass scales, respectively.

The study of atomic spectra is one of the key subjects in teaching physics. It represents a combination of topics such as wave physics, atomic physics, particle physics, etc. Because of its complexity, it takes a well-prepared student and a very creative and resourceful teacher for this subject to be adequately understood and comprehended. This article presents theoretical background with key points in physics that help teachers to better organize their preparation for students and different experimental sets for this specific experiment, such as Nikola Tesla’s transformer or some other high-voltage transformers. Another point of view for this experiment is a variety of subexperiment possibilities to choose from in the execution of this practical exercise. This article also brings some difficulties that both teachers and students experience while preparing or doing this experiment, such as lack of more profound quantum physics knowledge since the conventional approach in teaching this specific topic in high schools and universities focuses on an introductory course in the history of this topic-oriented towards early years of the 20th century.

There are several theoretical models proposing dark matter candidates as well as different experimental searches for dark matter, collider, and non-collider ones. One of the most intriguing dark matter candidates is missing information in the cosmos. This is based on the mass-energy-information equivalence principle presented by M Vopson [1]. This review presents the historical development of this principle from its roots in the 1960s when Landauer principle was firstly presented to the latest data on the estimated value of the mass of one bit of information as well as data on missing energy as potential dark matter. Another theoretical discussion presented here is the reformulation of the second law of thermodynamics as a possible step to great unification. In addition to this theoretical postulation with a mathematical presentation focusing on statistics, we present some of the proposed experiments in this field. Two major proposals are in the direction of using an ultra-accurate balance with measurement uncertainty low enough to be comparable with proposed theoretical limits, and originally developed sensitive interferometer similar to the one in LIGO experiment.

Dark matter as one of the cosmos’ ingredients or constituents has been searched for in various experiments. This review presents some of the searches for dark matter while focusing on the LHC mainly. In order to present various searches, it describes theoretical models followed by experimental verification. Since there are three types of searches, among which most significant are direct and indirect ones, we will give an overview and short comparison between the two, with an emphasis on the advantages and disadvantages of collider and non-collider searches. This review brings an argumentative approach for the collider’s point of view since searches for dark matter in colliders are veritably ambitious regarding direct and indirect Dark Matter detection methods. LHC starts its Run 3 in 2021, and here we present results from the ATLAS experiment from Run 2 and bring some theoretical expectations from LHC in Run 3.

Vertical temperature profiles represent a very important factor for various analytical and numerical studies, such as weather forecasts, air pollution models and CFD simulations. These temperature profiles are especially important during the winter periods, when temperature inversions occur. The cities in the natural valleys, such as the city of Sarajevo, B&H, are strongly affected by this phenomenon. In this paper, a method for quantitative characterization of vertical temperature profiles, which is based on the in-house developed data acquisition system and the unmanned aerial vehicle, is presented. Comprehensive calibration and verification procedure was performed and explained in details. Field measurements were focused on the winter period and extreme temperature inversion scenarios. The correlation with the air pollution in the city, for the same period, was discussed as well.