Unification in Particle Physics: Symmetries and Hidden Dimensions

The information on content, theory of operation and metrological concepts of the State primary special standard of length unit in the field of measurements of deviations from straightness and flatness, GET 130-2019, conducted in 2019, is provided. The results of metrological characteristics research of the measuring interference system included in GET 130-2019 are described. With the help of an additional measuring interference system, the unit is reproduced on the basis of fundamental physical constants and the properties of matter – interference, which eliminates additional instrumental sources of errors (uncertainties). The transfer of length in the field of measurements of deviations from straightness and flatness in the range from 0 to 50 μm on the length of the measured surface up to 30 m with the highest accuracy in Russia is ensured. The conducted comparisons proved that metrological characteristics of GET 130-2019 correspond to those presented in the database of measuring capabilities of the International Bureau of Weights and Measures (BIPM) on the already confirmed by means of stationary and autonomous measuring profile length to 5 m, as well as the level of foreign standards, presented in BIPM on the length to 30 m.

Papers of interest primarily to scientists working in these fields.This section covers a broad range of physical and chemical research, with major emphasis on standards of physical measurement, fundamental constants, and properties of matter.

The search for dark matter has been ongoing for decades within both astrophysics and particle physics. Both fields have employed different approaches and conceived a variety of methods for constraining the properties of dark matter, but have done so in relative isolation of one another. From an astronomer's perspective, it can be challenging to interpret the results of dark matter particle physics experiments and how these results apply to astrophysical scales. Over the past few years, the ESCAPE Dark Matter Test Science Project has been developing tools to aid the particle physics community in constraining dark matter properties; however, ESCAPE itself also aims to foster collaborations between research disciplines. This is especially important in the search for dark matter, as while particle physics is concerned with detecting the particles themselves, all of the evidence for its existence lies solely within astrophysics and cosmology. Here, we present a short review of the progress made by the Dark Matter Test Science Project and their applications to existing experiments, with a view towards how this project can foster complementary with astrophysical observations.

The fine structure constant can be represented in many ways depending on which fundamental constants and units are chosen. This confuses analysis in terms of dimensioned constants as the meaning changes depending on the unit system at hand. In this work a new global definition of the fine structure constant is given, which is independent of the unit representation. This is achieved by showing that it is proportional to the quanta of electric and magnetic flux of force of the electron. Thus, a variation is shown to manifest due to a differential change in the fraction of the quanta of electric and magnetic flux offeree of the electron. Conversely, fc is proportional to the product. The representation is discussed with respect to temporal drift, and the running of the fine structure constant at high energies (small distances). With regards to temporal drift, a proof is given, which shows that it is impossible Co determine which fundamental constant is varying if the fine structure constant varies. Also, it is shown that the running of the fine structure constant is due to equal components of electric screening (polarization of vacuum) and magnetic anti-screening (magnetization of vacuum), which cause the perceived quanta of electric charge to increase at small distances, while the magnetic flux quanta decreases. This introduces the concept of the 'bare magnetic flux quanta' as well as the 'bare electric charge .

The observational evidence for the recent acceleration of the universe shows that canonical theories of cosmology and particle physics are incomplete and that new physics is out there, waiting to be discovered. A compelling task for astrophysical facilities is to search for, identify and ultimately characterize this new physics. I present very recent developments in tests of the stability of nature's fundamental constants, as well as their impact on physics paradigms beyond the standard model. Specifically I discuss new observational constraints at low redshifts and at the BBN epoch, and highlight their different implications for canonical quintessence-type models and for non-canonical string-theory inspired models. Finally I also present new forecasts, based on realistic simulated data, of the gains in sensitivity for these constraints expected from ELT-HIRES, on its own and in combination with Euclid.

As we approach the turn of the century, the Standard Model is still\nconsistent with all our experimental observations and the path to a more\ncomplete picture of the fundamental constituents and their interactions has yet\nto be clearly identified. Beauty flavored hadrons have provided crucial\nexperimental information on several fundamental parameters of the Standard\nModel and may lead to one of the most challenging test of its validity and\nprovide some clues on the path towards a more complete theory. Several\nexperiments will try to explore this rich phenomenology in the next few years.\nTheir physics goals and discovery potential will be compared.\n

In order to understand how matter 15 billion years ago in the form of quarks, gluons and leptons at a temperature of 2 × 1012 °K evolved to become today’s Universe, the goal of relativistic and ultra-relativistic heavy ion physics is to understand the equation of state of nuclear, hadronic and partonic matter. This quest is of cross-disciplinary interest. The phase transition from partonic matter to hadronic matter tens of micro-seconds after the beginning of the universe is of interest to cosmology. Fluctuations during this phase transition would influence nucleosynthesis and the understanding of baryonic inhomogeneities in the universe. The nuclear matter equation of state, which describes the incompressibility of nuclear matter, governs neutron star stability. It determines the possible existence of strange quark matter stars and the dynamics of supernova expansion in astrophysics. The existence of collective nuclear phenomena in nuclear physics is also determined by the nuclear equation of state. In relativistic heavy ion collisions collective nuclear flow has been observed and is being studied extensively to obtain a better understanding of the incompressibility of nuclear matter. In high energy nuclear and particle physics, production and excitations of hadronic final states have been studied in detail and are important to an overall understanding of the equation of state of nuclear matter at finite temperature. The possibility in ultra-relativistic heavy ion collisions to create and study highly excited hadronic and partonic degrees of freedom provides a unique opportunity for understanding the behavior of nuclear, hadronic and partonic matter. Study of the QCD vacuum, of particular interest in particle physics, would provide a better understanding of symmetry-breaking mechanisms and the origins of the masses of the various quarks and particles. Creation and study of the quark-gluon plasma, an excitation of the QCD vacuum, is the goal of physicists in the new field of ultra-relativistic heavy ion collisions.

It is an exciting time for high energy physics. Several experiments are currently exploring uncharted terrain; the next generation of colliders will begin operation in the coming decade. These experiments will together help us understand some of the most puzzling issues in particle physics: the mechanism of electroweak symmetry breaking and the generation of flavor physics. It is clear that the primary goal of theoretical particle physics in the near future is to support and guide this experimental program. These tasks can be accomplished in two ways: by developing experimental signatures for new models which address outstanding problems, and by improving Standard Model predictions for precision observables. We present here several results which advance both of these goals. We begin with a study of non-commutative field theories. It has been suggested that TeV-scale non-commutativity could explain the origin of CP violation in the SM. We identify several distinct signatures of non-commutativity in high energy processes. We also demonstrate the one-loop quantum consistency of a simple spontaneously broken non-commutative U(1) theory; this result is an important preface to any attempt to embed the SM within a non-commutative framework. We then investigate the phenomenology of extra-dimensional theories, which have been suggested recently as solutions to the hierarchy problem of particle physics. We first examine the implications of allowing SM fields to propagate in the full five-dimensional spacetime of the Randall-Sundrum model, which solves the hierarchy problem via an exponential ''warping'' of the Planck scale induced by a five-dimensional anti de-Sitter geometry. In an alternative extra-dimensional theory, in which all SM fields are permitted to propagate in flat extra dimensions, we show that properties of the Higgs boson are significantly modified. Finally, we discuss the next-to-next-to leading order QCD corrections to the dilepton rapidity distribution in the Drell-Yan process, an important discovery channel for new physics at hadron colliders. We introduce a powerful new method for calculating differential distributions in hard scattering processes. We apply our results to the analysis of fixed target experiments, which provide important constraints on the parton distribution functions of the proton.

This article reviews the discovery of the Higgs boson, discusses the studies of its properties, and introduces the physical prospects of the future Higgs factories. The greatest goal of particle physics is to understand the fundamental particles of the universe and how they interact with each other (or more generally, how the universe operates). In the standard model of particle phyiscs, the Higgs mechanism is proposed to explain the origin of elementary particle mass and predict the existence of the Higgs boson. Higgs physics is one of the most important research areas in particle physics. The Large Hadron Collider (LHC) at CERN (Geneva, Switzerland) accelerates proton beams to collide at center-of-mass energy of 13 TeV, thus defining the world’s energy frontier. The ATLAS and CMS detectors are two general-purpose detectors at the LHC for studying the debris from the collisions. The Higgs boson was discovered in the ATLAS and CMS experiments in 2012. This discovery completed the fundamental particle spectrum of the standard model and was an important milestone for particle physics. Since then, many studies have been conducted on the properties of Higgs boson, including spin, mass and couplings, to deepen our understanding of the Higgs mechanism. In particular, the Higgs boson couplings to fermions and to themselves present new kinds of fundamental interactions with paramount significance, which have not been fully confirmed. Additionally, the Higgs bosons has become an important tool to search for dark matter, heavy resonance, and other new physical phenomena. So far, there has been no deviation from the predictions of the standard model. Looking forward to the future, it is proposed to use the electron-positron collisions to study the Higgs boson in more depth. Physics studies have shown that these Higgs factories can significantly improve the accuracy of many properties of the Higgs boson, including width and couplings, and provide great physics prospects.

X‐ray spectroscopy is one of the most powerful tools to access structure and properties of matter in different states of aggregation as it allows to trace atomic and molecular energy levels in course of various physical and chemical processes. X‐ray spectroscopic techniques probe the local electronic structure of a particular atom in its environment, in contrast to ultraviolet/visible (UV/Vis) spectroscopy, where transitions generally occur between delocalized molecular orbitals. Complementary information is provided by using a combination of different absorption, emission, scattering as well as photo‐ and autoionization X‐ray methods. However, interpretation of the complex experimental spectra and verification of experimental hypotheses is a nontrivial task and powerful first principles theoretical approaches that allow for a systematic investigation of a broad class of systems are needed. Focusing on transition metal compounds, L‐edge spectra are of particular relevance as they probe the frontier d‐orbitals involved in metal–ligand bonding. Here, near‐degeneracy effects in combination with spin‐orbit coupling lead to a complicated multiplet energy level structure, which poses a serious challenge to quantum chemical methods. Multiconfigurational self‐consistent field (MCSCF) theory has been shown to be capable of providing a rather detailed understanding of experimental X‐ray spectroscopy. However, it cannot be considered as a “blackbox” tool and its application requires not only a command of formal theoretical aspects, but also a broad knowledge of already existing applications. Both aspects are covered in this overview.This article is categorized under: Theoretical and Physical Chemistry > Spectroscopy Electronic Structure Theory > Ab Initio Electronic Structure Methods

In order to study the origin of the fundamental constants and Dirac's large number, a cosmological solution in vacuum is presented in a seven-dimensional universe which is defined by adding extra three coordinates (e2G/c4)1/2, (hG/c3)1/2 and (Gm/c2) to the four-dimensional spacetime coordinates. It has common features with Chodos-Detweiler's solution. The parameters appearing in this theory are estimated to meet the conditions required by the cosmological first-order phase transition and Dirac's large number hypothesis.

The metrological fields of photometry and radiometry and their associated units are closely linked through the current definition of the base unit of luminous intensity—the candela. These fields are important to a wide range of applications requiring precise and accurate measurements of electromagnetic radiation and, in particular, the amount of radiant energy (light) that is perceived by the human eye. The candela has been one of the base units since the inception of the International System of Units (SI) and is the only base unit that quantifies a fundamental biological process—human vision. This photobiological process spans an enormous dynamic range of light levels from a few-photon interaction involved in triggering the vision mechanism to a level of more than 1015 photons per second that is accommodated by the visual response under bright daylight conditions. This position paper, prepared by members of the Task Group on the SI of the Consultative Committee for Photometry and Radiometry Strategic Planning Working Group (CCPR WG-SP), reviews the evolution of these fields of optical radiation measurements and their consequent impact on definitions and realization of the candela. Over the past several decades, there have been significant developments in sources, detectors, measuring instruments and techniques, that have improved the measurement of photometric and radiometric quantities for classical applications in lighting design, manufacturing and quality control processes involving optical sources, detectors and materials. These improved realizations largely underpin the present (1979) definition of the candela. There is no consensus on whether this radiant-based definition fully satisfies the current and projected needs of the optical radiation community. There is also no consensus on whether a reformulation of the definition of the candela in terms of photon flux will be applicable to the lighting community. However, there have been significant recent advances in radiometry in the development of single-photon sources and single-photon detectors and the growth of associated technologies, such as quantum computing and quantum cryptography. The international acceptance of these new quantum-based technologies requires improved traceability and reliability of measurements at the level of a few photons. This review of the evolution of the candela and the impact of its possible reformulation might lead, in the future, to a reformulation in terms of quantum units (photons). This discussion is timely since redefinitions of four of the other SI base units are being considered now in terms of fundamental constants to provide a more universally realizable quantum-based SI system. This paper also introduces for the first time a fundamental constant for photometry.

A closed form expression of a quadruple integral involving the Hermite polynomial Hn(x) is derived. Special cases are expressed in terms of special functions and fundamental constants. All the results in this work are new.

The main goal of fundamental particle physics is to identify the basic building blocks of nature, un…

Towards the hadron–quark continuity via a topology change in compact stars