Cosmology and elementary particles, or celestial mysteries
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smology and Elementary Particles, or Celestial Mysteries A. D. Dolgov University of Ferrara and INFN, Ferrara, FE44100 Italy Institute for Theoretical and Experimental Physics, Moscow, 117218 Russia email: [email protected] Abstract—This is an extended version of the report at Round Table 2, Italy–Russia Dubna “Space Physics and Biology.” Given the diversity of the audience, this paper provides a popular description of the cosmolog ical problems which can be solved only by introduction of new phenomena beyond the minimal standard model of particle physics. The cosmological dark and vacuum energy, dark matter, inflation, and baryogenesis are discussed. In the conclusion, possibilities for a fundamental change in the laws of modern physics are briefly discussed. DOI: 10.1134/S1063779612030033
1. INTRODUCTION Over the last 30 years of the previous century, two great fundamental theories were proposed that are in perfect agreement with experiments and astronomical observations with the exception of a few “little clouds.” These remarkable theories are: (1) Minimal standard model in particle physics (MSM), which classifies all known particles and describes all their known interactions, i.e., elec troweak and strong interactions. (2) Standard cosmological model (SCM), which describes the evolution of the universe from the “beginning” to this day. However, there is a “subtle” problem with these theories: their phenomenology being perfectly consis tent with observations/experiment, they do not fit each other well at a deeper level, strongly implying the need for a new, perhaps totally unexpected physics to explain the observed picture. The minimal standard model has the following set of elementary particles, and no other particles are required. These are, firstly, three families of quarks, each of which consists of a pair of quarks, an upper and a lower one: (u, d), (c, s), and (t, b). The charge of upper quarks is (+2/3)e; that of the lower quarks is (–1/3)e, where e is the absolute value of the electron charge. Each of the six quarks has three colors, and their prop erties do not depend on the color. However, the prop erties of the quarks depend on the family they belong to. First and foremost, their masses are very different [1]: mu ≈ 2.5 MeV, md ≈ 5 MeV, mc = 1.27 GeV, ms ≈100 MeV, mt ≈170 GeV, and mb ≈ 4.5 GeV. All the quarks, except for the t quark, are detected in a direct experiment, and the latter is seen from the analysis of radiative corrections to the weak interaction. I would like to note that the quarks are not found in isolation,
but only in a bound form, as a part of elementary par ticles. For each family of quarks, there is a corresponding family of leptons: (e–, νe), (μ–, νμ) and (τ–, ντ). All the neutrinos are almost massless, whereas the masses of the charged leptons differ quite considerably: me = 0.511 MeV, mμ = 105 MeV, and mτ ≈ 1.78 GeV. Unlike quarks, leptons are colorless and, therefore, do not participate in strong interactions. No differences in the electroweak interactions of leptons of d
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