Quantum Field Theory at the Limits: From Strong Fields to Heavy Quarks

A special issue of Particles (ISSN 2571-712X).

Deadline for manuscript submissions: closed (31 May 2020) | Viewed by 30052

Special Issue Editors

Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia
Interests: effective field theories; hadron physics; physics beyond SM
Special Issues, Collections and Topics in MDPI journals
1. Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia
2. Institute of Nuclear Physics, Ministry of Energy of the Republic of Kazakhstan, 050032 Almaty, Kazakhstan
3. Al-Farabi Kazakh National University, SRI for Mathematics and Mechanics, 050038 Almaty, Kazakhstan
1. Helmholtz Institute Jena, Fröbelstieg 3, 07743 Jena, Germany
2. Friedrich Schiller Universität Jena, Max Wien Place 1, 07743 Jena, Germany
1. Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
2. Institute of Theoretical Physics, Technical University Dresden, 01062 Dresden, Germany

Special Issue Information

Dear colleagues,

We are happy to announce that Particles and the organizers of the Helmholtz International Summer School “Quantum Field Theory at the Limits: From Strong Fields to Heavy Quarks will collaborate to produce a Special Issue volume, for extended versions of selected papers from this event (http://indico.jinr.ru/event/797/).

This Special Issue will cover the main topics in heavy-flavor and strong-field physics. One focus is on latest results on heavy quark physics from all four experimental collaborations at the LHC (ATLAS, CMS, LHCb, ALICE) and from the B-factory at the KEK. The second focus concentrates on the high-intensity frontier and extreme states of matter as probed by current and upcoming high-power laser and high-Z ion facilities all around the world. Leading experts in these fields contributed to a series of lectures devoted to theoretical predictions and analyses of experiments. Students and young scientists presented results of their graduation theses and original research results.

As the Guest Editors, we would like to invite you to submit your unpublished and original research relevant to this topic for publication in this Special Volume of Particles. All submissions will be peer-reviewed by internationally recognized experts. The Article Processing Charge (APC) for submissions from the conference will be free of charge.

Prof. Dr. David Blaschke
Prof. Dr. Mikhail Ivanov
Dr. Aidos Issadykov
Prof. Dr. Holger Gies
Prof. Dr. Ralf Schützhold
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Particles is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Flavor physics and CP-violation
  • Beyond the Standard Model
  • Effective theories and models in heavy quark physics
  • b-hadrons and their decays
  • Top quark physics
  • XYZ states
  • Strong-field QED
  • High-intensity plasma physics
  • Production and transport of heavy flavours in nuclear collisions

Published Papers (13 papers)

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Research

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21 pages, 1159 KiB  
Article
Kinetic Equation Approach to Graphene in Strong External Fields
by Stanislav A. Smolyansky, Anatolii D. Panferov, David B. Blaschke and Narine T. Gevorgyan
Particles 2020, 3(2), 456-476; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3020032 - 12 Jun 2020
Cited by 6 | Viewed by 2141
Abstract
The report presents the results of using the nonperturbative kinetic approach to describe the excitation of plasma oscillations in a graphene monolayer. As examples the constant electric field as well as an electric field of short high-frequency pulses are considered. The dependence of [...] Read more.
The report presents the results of using the nonperturbative kinetic approach to describe the excitation of plasma oscillations in a graphene monolayer. As examples the constant electric field as well as an electric field of short high-frequency pulses are considered. The dependence of the induced conduction and polarization currents characteristics on the pulse intensity, pulse duration, and polarization is investigated. The characteristics of secondary electromagnetic radiation resulting from the alternating currents is investigated. The nonlinear response to the external electric field characterizes graphene as an active medium. Qualitative agreement is obtained with the existing experimental result of measurements of currents in constant electric fields and radiation from graphene in the case of excitation by means of the infrared and optical pulses. Full article
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50 pages, 1120 KiB  
Article
About Calculation of Massless and Massive Feynman Integrals
by Anatoly V. Kotikov
Particles 2020, 3(2), 394-443; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3020030 - 07 May 2020
Cited by 6 | Viewed by 2353
Abstract
We report some results of calculations of massless and massive Feynman integrals particularly focusing on difference equations for coefficients of for their series expansions. Full article
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16 pages, 609 KiB  
Article
Space Dimension Renormdynamics
by Martin Bures and Nugzar Makhaldiani
Particles 2020, 3(2), 364-379; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3020028 - 17 Apr 2020
Viewed by 1696
Abstract
We aim to construct a potential better suited for studying quarkonium spectroscopy. We put the Cornell potential into a more geometrical setting by smoothly interpolating between the observed small and large distance behaviour of the quarkonium potential. We construct two physical models, where [...] Read more.
We aim to construct a potential better suited for studying quarkonium spectroscopy. We put the Cornell potential into a more geometrical setting by smoothly interpolating between the observed small and large distance behaviour of the quarkonium potential. We construct two physical models, where the number of spatial dimensions depends on scale: one for quarkonium with Cornell potential, another for unified field theories with one compactified dimension. We construct point charge potential for different dimensions of space. The same problem is studied using operator fractal calculus. We describe the quarkonium potential in terms of the point charge potential and identify the strong coupling fine structure constant dynamics. We formulate renormdynamics of the structure constant in terms of Hamiltonian dynamics and solve the corresponding motion equations by numerical and graphical methods, we find corresponding asymptotics. Potentials of a nonlinear extension of quantum mechanics are constructed. Such potentials are ingredients of space compactification problems. Mass parameter effects are motivated and estimated. Full article
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11 pages, 558 KiB  
Article
Heavy Baryon Spectroscopy in the Relativistic Quark Model
by Rudolf N. Faustov and Vladimir O. Galkin
Particles 2020, 3(1), 234-244; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010019 - 16 Mar 2020
Cited by 11 | Viewed by 2176
Abstract
Masses of heavy baryons are calculated in the framework of the relativistic quark-diquark picture and QCD. The obtained results are in good agreement with available experimental data including recent measurements by the LHCb Collaboration. Possible quantum numbers of excited heavy baryon states are [...] Read more.
Masses of heavy baryons are calculated in the framework of the relativistic quark-diquark picture and QCD. The obtained results are in good agreement with available experimental data including recent measurements by the LHCb Collaboration. Possible quantum numbers of excited heavy baryon states are discussed. Full article
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11 pages, 7270 KiB  
Article
Detectable Optical Signatures of QED Vacuum Nonlinearities Using High-Intensity Laser Fields
by Leonhard Klar
Particles 2020, 3(1), 223-233; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010018 - 06 Mar 2020
Cited by 8 | Viewed by 1982
Abstract
Up to date, quantum electrodynamics (QED) is the most precisely tested quantum field theory. Nevertheless, particularly in the high-intensity regime it predicts various phenomena that so far have not directly been accessible in all-optical experiments, such as photon-photon scattering phenomena induced by quantum [...] Read more.
Up to date, quantum electrodynamics (QED) is the most precisely tested quantum field theory. Nevertheless, particularly in the high-intensity regime it predicts various phenomena that so far have not directly been accessible in all-optical experiments, such as photon-photon scattering phenomena induced by quantum vacuum fluctuations. Here, we focus on all-optical signatures of quantum vacuum effects accessible in the high-intensity regime of electromagnetic fields. We present an experimental setup giving rise to signal photons distinguishable from the background. This configuration is based on two optical pulsed petawatt lasers: one generates a narrow but high-intensity scattering center to be probed by the other one. We calculate the differential number of signal photons attainable with this field configuration analytically and compare it with the background of the driving laser beams. Full article
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15 pages, 680 KiB  
Article
Semileptonic Decays of Heavy Baryons in the Relativistic Quark Model
by Rudolf N. Faustov and Vladimir O. Galkin
Particles 2020, 3(1), 208-222; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010017 - 06 Mar 2020
Cited by 7 | Viewed by 2084
Abstract
Semileptonic and rare semileptonic decays of heavy baryons are studied in the framework of the relativistic quark model based on the quark-diquark picture, quasipotential approach, and quantum chromodynamics (QCD). The form factors parametrizing the matrix elements of the weak transitions are calculated in [...] Read more.
Semileptonic and rare semileptonic decays of heavy baryons are studied in the framework of the relativistic quark model based on the quark-diquark picture, quasipotential approach, and quantum chromodynamics (QCD). The form factors parametrizing the matrix elements of the weak transitions are calculated in the whole accessible kinematical range with the comprehensive account of the relativistic effects. The obtained results for the branching ratios and other observables agree well with the available experimental data. Full article
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15 pages, 858 KiB  
Article
D * Polarization as an Additional Constraint on New Physics in the b ν ¯ τ Transition
by Mikhail A. Ivanov, Jürgen G. Körner, Pietro Santorelli and Chien-Thang Tran
Particles 2020, 3(1), 193-207; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010016 - 05 Mar 2020
Cited by 6 | Viewed by 2146
Abstract
Measurements of the branching fractions of the semileptonic decays B D ( * ) τ ν ¯ τ and B c J / ψ τ ν ¯ τ systematically exceed the Standard Model predictions, pointing to possible signals of new physics [...] Read more.
Measurements of the branching fractions of the semileptonic decays B D ( * ) τ ν ¯ τ and B c J / ψ τ ν ¯ τ systematically exceed the Standard Model predictions, pointing to possible signals of new physics that can violate lepton flavor universality. The unknown origin of new physics realized in these channels can be probed using a general effective Hamiltonian constructed from four-fermion operators and the corresponding Wilson coefficients. Previously, constraints on these Wilson coefficients were obtained mainly from the experimental data for the branching fractions. Meanwhile, polarization observables were only theoretically studied. The situation has changed with more experimental data having become available, particularly those regarding the polarization of the tau and the D * meson. In this study, we discuss the implications of the new data on the overall picture. We then include them in an updated fit of the Wilson coefficients using all hadronic form factors from our covariant constituent quark model. The use of our form factors provides an analysis independent of those in the literature. Several new-physics scenarios are studied with the corresponding theoretical predictions provided, which are useful for future experimental studies. In particular, we find that under the one-dominant-operator assumption, no operator survives at 1 σ . Moreover, the scalar operators O S L and O S R are ruled out at 2 σ if one uses the constraint B ( B c τ ν τ ) 10 % , while the more relaxed constraint B ( B c τ ν τ ) 30 % still allows these operators at 2 σ , but only minimally. The inclusion of the new data for the D * polarization fraction F L D * reduces the likelihood of the right-handed vector operator O V R and significantly constrains the tensor operator O T L . Specifically, the F L D * alone rules out O T L at 1 σ . Finally, we show that the longitudinal polarization P L τ of the tau in the decays B D * τ ν ¯ τ and B c J / ψ τ ν ¯ τ is extremely sensitive to the tensor operator. Within the 2 σ allowed region, the best-fit value T L = 0.04 + i 0.17 predicts P L τ ( D * ) = 0.33 and P L τ ( J / ψ ) = 0.34 , which are at about 33% larger than the Standard Model (SM) prediction P L τ ( D * ) = 0.50 and P L τ ( J / ψ ) = 0.51 . Full article
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22 pages, 423 KiB  
Article
Nonleptonic Decays of Doubly Charmed Baryons
by Mikhail A. Ivanov
Particles 2020, 3(1), 123-144; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010011 - 19 Feb 2020
Cited by 2 | Viewed by 1665
Abstract
In this lecture, we provide a basic introduction into the topic of charmed baryons and their nonleptonic two-body decays. Some features of the baryon weak decays on the quark level are discussed in detail in the framework of effective field theory. The calculation [...] Read more.
In this lecture, we provide a basic introduction into the topic of charmed baryons and their nonleptonic two-body decays. Some features of the baryon weak decays on the quark level are discussed in detail in the framework of effective field theory. The calculation of the matrix elements of the four-quark operators arising in the effective theory proceeds by using the covariant constituent quark model. The model allows one to evaluate not only the factorizing tree-level diagrams but also more complicated diagrams with the internal W–exchange. The technique required for such calculation is discussed in some detail. Finally, the numerical results are presented, and comparison of the contributions coming from the W–exchange diagrams with those from the tree-level are carefully performed. Full article
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15 pages, 474 KiB  
Article
Analytic Properties of Triangle Feynman Diagrams in Quantum Field Theory
by Dmitri Melikhov
Particles 2020, 3(1), 99-113; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010009 - 12 Feb 2020
Cited by 1 | Viewed by 2903
Abstract
We discuss dispersion representations for the triangle diagram F ( q 2 , p 1 2 , p 2 2 ) , the single dispersion representation in q 2 and the double dispersion representation in p 1 2 and p 2 2 , [...] Read more.
We discuss dispersion representations for the triangle diagram F ( q 2 , p 1 2 , p 2 2 ) , the single dispersion representation in q 2 and the double dispersion representation in p 1 2 and p 2 2 , with special emphasis on the appearance of the anomalous singularities and the anomalous cuts in these representations. Full article
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Review

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27 pages, 500 KiB  
Review
Effective Field Theories
by Andrey Grozin
Particles 2020, 3(2), 245-271; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3020020 - 31 Mar 2020
Cited by 5 | Viewed by 2337
Abstract
This paper represents a pedagogical introduction to low-energy effective field theories. In some of them, heavy particles are “integrated out” (a typical example—the Heisenberg–Euler EFT); in some, heavy particles remain but some of their degrees of freedom are “integrated out” (Bloch–Nordsieck EFT). A [...] Read more.
This paper represents a pedagogical introduction to low-energy effective field theories. In some of them, heavy particles are “integrated out” (a typical example—the Heisenberg–Euler EFT); in some, heavy particles remain but some of their degrees of freedom are “integrated out” (Bloch–Nordsieck EFT). A large part of these lectures is, technically, in the framework of QED. QCD examples, namely decoupling of heavy flavors and HQET, are discussed only briefly. However, effective field theories of QCD are very similar to the QED case, and there are just some small technical complications: more diagrams, color factors, etc. The method of regions provides an alternative view at low-energy effective theories; this is also briefly introduced. Full article
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19 pages, 3174 KiB  
Review
Probes of Lepton Flavor Universality in bu Transitions
by Pietro Colangelo, Fulvia De Fazio and Francesco Loparco
Particles 2020, 3(1), 145-163; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010012 - 27 Feb 2020
Cited by 1 | Viewed by 1896
Abstract
Anomalies recently observed in semileptonic b c ν ¯ and b s + transitions point to violation of Lepton Flavour Universality. Strategies for new analyses of different modes are required, in particular for the modes [...] Read more.
Anomalies recently observed in semileptonic b c ν ¯ and b s + transitions point to violation of Lepton Flavour Universality. Strategies for new analyses of different modes are required, in particular for the modes induced by the b u transition. We describe the purely leptonic B decay, the B ¯ π ν ¯ channel and the B semileptonic modes to ρ ( 770 ) and a 1 ( 1260 ) in extensions of the Standard Model involving Lepton Flavour Universality violating b u operators. In particular, we review the observables in the four-dimensional angular B ¯ ρ ( π π ) ν ¯ and B ¯ a 1 ( ρ π ) ν ¯ distributions, suitable to pin down deviations from the Standard Model. We discuss the complementarity among the various modes for New Physics searches. Full article
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23 pages, 527 KiB  
Review
Probing Vacuum Polarization Effects with High-Intensity Lasers
by Felix Karbstein
Particles 2020, 3(1), 39-61; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010005 - 19 Jan 2020
Cited by 44 | Viewed by 3599
Abstract
These notes provide a pedagogical introduction to the theoretical study of vacuum polarization effects in strong electromagnetic fields as provided by state-of-the-art high-intensity lasers. Quantum vacuum fluctuations give rise to effective couplings between electromagnetic fields, thereby supplementing Maxwell’s linear theory of classical electrodynamics [...] Read more.
These notes provide a pedagogical introduction to the theoretical study of vacuum polarization effects in strong electromagnetic fields as provided by state-of-the-art high-intensity lasers. Quantum vacuum fluctuations give rise to effective couplings between electromagnetic fields, thereby supplementing Maxwell’s linear theory of classical electrodynamics with nonlinearities. Resorting to a simplified laser pulse model, allowing for explicit analytical insights, we demonstrate how to efficiently analyze all-optical signatures of these effective interactions in high-intensity laser experiments. Moreover, we highlight several key features relevant for the accurate planning and quantitative theoretical analysis of quantum vacuum nonlinearities in the collision of high-intensity laser pulses. Full article
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Other

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5 pages, 407 KiB  
Conference Report
The DsTau Experiment: A Study for Tau-Neutrino Production
by Mădălina Mihaela Miloi and [DsTau Collaboration]
Particles 2020, 3(1), 164-168; https://0-doi-org.brum.beds.ac.uk/10.3390/particles3010013 - 01 Mar 2020
Viewed by 2257
Abstract
For clarifying the validity of the Lepton Universality hypothesis, one of the fundamental statements of the Standard Model, the interaction cross section for all three flavors of leptons have to be known with high precision. In neutrino sector, for electron and muon neutrinos, [...] Read more.
For clarifying the validity of the Lepton Universality hypothesis, one of the fundamental statements of the Standard Model, the interaction cross section for all three flavors of leptons have to be known with high precision. In neutrino sector, for electron and muon neutrinos, the interaction cross section is known fairly well, but for tau neutrino only poor estimations exist. In particular, the most direct measurement by the DONuT experiment was performed with rather poor accuracy due to low statistics and an uncertainty of the tau neutrino flux. The DsTau experiment proposes to study tau-neutrino production process and thus to improve significantly the accuracy of calculations of tau neutrino flux for neutrino accelerator experiments. To study reactions providing most of tau neutrinos, the experiment uses a setup based on high resolution nuclear emulsions, capable to register short lived particle decays created in proton-nucleus interactions. The present report is an overview of the DsTau experiment together with some of the preliminary results from the pilot run. Full article
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