Thu·Sep 28, 2017Thursday·September 28, 2017

1. 01*

   Study of rare mesonic decays involving di-neutrinos in their final state

   Azeem Mir🇵🇰 · Farida Tahir🇵🇰 · Shakeel Mahmood🇵🇰 · Shi- Hai Dong🇵🇰

   We have carried out phenomenological implication of R-parity violating ($\text{NEG}$) Minimal Supersymmetric Model (MSSM) via analyses of pure leptonic() and semileptonic decays of pseudo-scalar mesons(% $M\to X\nu \bar{\nu }$). These analyses involve prediction of branching fraction of pure leptonic decays by using experimental limits/bounds derived from the study of semileptonic decays on $\text{NEG}{R}_p$ parameters. We have found, in general that $\text{NEG}{R}_p$ contribution dominates over the SM contribution i.e., by a factor of $10^2$ for the semleptonic decays of $K^0$, $10$ for the pure leptonic decays of $K_{L,S}$ , while $10^2$\& $10^4$ in case of $B_s$ and $B_d$ respectively. This demonstrates the role of $\text{NEG}{R}_p$ as a viable model for the study of NP contribution in rare decays.

   hep-phAdv.High Energy Phys.(2018)·1 citation
2. 02*

   A Clifford Algebra Approach to Chiral Symmetry Breaking and Fermion Mass Hierarchies

   Wei Lu🇺🇸

   We propose a Clifford algebra approach to chiral symmetry breaking and fermion mass hierarchies in the context of composite Higgs bosons. Standard model fermions are represented by algebraic spinors of six-dimensional binary Clifford algebra, while ternary Clifford algebra-related flavor projection operators control allowable flavor-mixing interactions. There are three composite electroweak Higgs bosons resulted from top quark, tau neutrino, and tau lepton condensations. Each of the three condensations gives rise to masses of four different fermions. The fermion mass hierarchies within these three groups are determined by four-fermion condensations, which break two global chiral symmetries. The four-fermion condensations induce axion-like pseudo-Nambu-Goldstone bosons and can be dark matter candidates. In addition to the 125 GeV Higgs boson observed at the Large Hadron Collider, we anticipate detection of tau neutrino composite Higgs boson via the charm quark decay channel.

   hep-phhep-thInt.J.Mod.Phys.A(2017)·6 citations
3. 03*

   The S- and P-wave low-lying baryons in the chiral quark model

   Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸

   The $1S$, $2S$, $1P$ and $2P$ states of light baryons are investigated within the chiral quark model, paying particular attention to the well-known order reverse problem of $1P$ and $2S$ states. Besides a nonperturbative linear-screened confining interaction and a perturbative one-gluon exchange between quarks, we incorporate the Goldstone-boson exchanges taking into account not only the full octet of pseudoscalar mesons but also the scalar one. The scalar meson exchange potential simulates the higher order multi-pion exchange terms that appear in the chiral Lagrangian and its omission has been already admitted as a deficiency of the original model in describing, for instance, the $\rho -\omega$ splitting. The numerical approach to the three body bound state problem is the so-called Gaußian expansion method, which is able to get a precision as good as Faddeev calculations. With a set of parameters fixed to different hadron and hadron-hadron observables, we find that the chiral potential could play an important role towards the issue on the mass order reverse problem. We extend our calculation to the $qqQ$ and $qQQ$ sectors (with $q$ representing a light $u$-, $d$-, or $s$-quark and $Q$ denoting the charm quark or the bottom one) in which many new states have been recently observed. Some tentative assignments are done attending to the agreement between theoretical and experimental masses; however, we admit that other sources of information are needed in order to make strong claims about the nature of these states.

   hep-phnucl-thFew Body Syst.(2018)·58 citations
4. 04*

   $Z$-boson decays to a vector quarkonium plus a photon

   Geoffrey T. Bodwin (Argonne)🇺🇸 · Hee Sok Chung (CERN)🇨🇭 · June-Haak Ee🇰🇷 · Jungil Lee (Korea U.)🇰🇷

   We compute the decay rates for the processes $Z\to V+\gamma$, where $Z$ is the $Z$ boson, $\gamma$ is the photon, and $V$ is one of the vector quarkonia $J/\psi$ or ${\rm Y}(nS)$, with $n=1$, $2$, or $3$. Our computations include corrections through relative orders ${\alpha }_s$ and $v^2$ and resummations of logarithms of $m_Z^2/m_Q^2$, to all orders in ${\alpha }_s$, at NLL accuracy. ($v$ is the velocity of the heavy quark $Q$ or the heavy antiquark $\bar{Q}$ in the quarkonium rest frame, and $m_Z$ and $m_Q$ are the masses of $Z$ and $Q$, respectively.) Our calculations are the first to include both the order-${\alpha }_s$ correction to the light-cone distributions amplitude and the resummation of logarithms of $m_Z^2/m_Q^2$ and are the first calculations for the ${\rm Y}(2S)$ and ${\rm Y}(3S)$ final states. The resummations of logarithms of $m_Z^2/m_Q^2$ that are associated with the order-${\alpha }_s$ and order-$v^2$ corrections are carried out by making use of the Abel-Padé method. We confirm the analytic result for the order-$v^2$ correction that was presented in a previous publication, and we correct the relative sign of the direct and indirect amplitudes and some choices of scales in that publication. Our branching fractions for $Z\to J/\psi +\gamma$ and $Z\to {\rm Y}(1S)+\gamma$ differ by $2.0\sigma$ and $-4.0\sigma$, respectively, from the branching fractions that are given in the most recent publication on this topic (in units of the uncertainties that are given in that publication). However, we argue that the uncertainties in the rates are underestimated in that publication.

   hep-phPRD(2018)·33 citations
5. 05*

   Cosmological implications of Standard Model criticality and Higgs inflation

   Yuta Hamada🇯🇵 · Hikaru Kawai🇯🇵 · Yukari Nakanishi🇯🇵 · Kin-ya Oda🇯🇵

   The observed Higgs mass indicates that the Standard Model can be valid up to near the Planck scale $M_{\text{P}}$. Within this framework, it is important to examine how little modification is necessary to fit the recent experimental results in particle physics and cosmology. As a minimal extension, we consider the possibility that the Higgs field plays the role of inflaton and that the dark matter is the Higgs-portal scalar field. We assume that the extended Standard Model is valid up to the string scale $10^{17}\text{GeV}$. (This translates to the assumption that all the non-minimal couplings are not particularly large, $\xi \lesssim 10^2$, as in the critical Higgs inflation, since $M_{\text{P}}/\sqrt{10^2}\sim 10^{17}\text{GeV}$.) We find a correlated theoretical bound on the tensor-to-scalar ratio $r$ and the dark matter mass $m_{\text{DM}}$. As a result, the Planck bound $r<0.09$ implies that the dark-matter mass must be smaller than 1.1\,TeV, while the PandaX-II bound on the dark-matter mass $m_{\text{DM}}>0.7\pm 0.2\text{TeV}$ leads to $r\gtrsim 2\times 10^{-3}$. Both are within the range of near-future detection. When we include the right-handed neutrinos of mass $M_{\text{R}}\sim 10^{14}$\,GeV, the allowed region becomes wider, but we still predict $r\gtrsim 10^{-3}$ in the most of the parameter space. The most conservative bound becomes $r>10^{-5}$ if we allow three-parameter tuning of $m_{\text{DM}}$, $M_{\text{R}}$, and the top-quark mass.

   hep-phastro-ph.COhep-thNPB(2020)·13 citations
6. 06*

   Bose-Einstein condensation in heavy ion collisions: importance of and uncertainties in the finite volume corrections

   Kacper Zalewski🇵🇱

   The density of the Bose-Einstein condensate for non-interacting pions in a cubic box, at given temperature and (average) total pion density, is calculaated for three sets of boundary conditions. The densities are much larger than predicted from thermodynamics and depend significantly on the choice of the boundary conditions, even for volumes as large as $6.4\cdot 10$fm${}^3$.

   hep-phnucl-th0 citations
7. 07*

   Two-Higgs-doublet model fits with HEPfit

   Otto Eberhardt🇪🇸

   The Two-Higgs-doublet model (2HDM) is one of the most studied extensions of the Standard Model. Like the other popular "New Physics" models, it gets more and more constrained by recent experimental progress, especially by the LHC data. For the 2HDM types I and II with a softly broken ${\mathbb{Z}}_2$ symmetry, I present updated results of global analyses obtained with the open-source HEPfit code, emphasizing the impact of the pre-EPS-HEP 2017 LHC data. Furthermore, I discuss the status of implementation into HEPfit of 2HDM's beyond the conventional ${\mathbb{Z}}_2$ symmetric types.

   hep-phhep-ex7 citations
8. 08*

   The Madala hypothesis with Run 1 and 2 data at the LHC

   Stefan von Buddenbrock🇿🇦 · Alan S. Cornell🇿🇦 · Mukesh Kumar🇿🇦 · Bruce Mellado🇿🇦

   The Madala hypothesis postulates a new heavy scalar, H, which explains several independent anomalous features seen in ATLAS and CMS data simultaneously. It has already been discussed and constrained in the literature by Run 1 results, and its underlying theory has been explored under the interpretation of a two Higgs doublet model coupled with a scalar singlet, $S$. When applying the hypothesis to Run 2 results, it can be shown that the constraints from the data are compatible with those obtained using Run 1 results.

   hep-phJ.Phys.Conf.Ser.(2017)·7 citations
9. 09*

   On the Possibility to Determine Neutrino Mass Hierarchy via Supernova Neutrinos with Short-Time Characteristics

   Junji Jia🇨🇳 · Yaoguang Wang🇨🇳 · Shun Zhou🇨🇳

   In this paper, we investigate whether it is possible to determine the neutrino mass hierarchy via a high-statistics and real-time observation of supernova neutrinos with short-time characteristics. The essential idea is to utilize distinct times-of-flight for different neutrino mass eigenstates from a core-collapse supernova to the Earth, which may significantly change the time distribution of neutrino events in the future huge water-Cherenkov and liquid-scintillator detectors. For illustration, we consider two different scenarios. The first case is the neutronization burst of ${\nu }_e^{}$ emitted in the first tens of milliseconds of a core-collapse supernova, while the second case is the black hole formation during the accretion phase for which neutrino signals are expected to be abruptly terminated. In the latter scenario, it turns out only when the supernova is at a distance of a few Mpc and the fiducial mass of the detector is at the level of gigaton, might we be able to discriminate between normal and inverted neutrino mass hierarchies. In the former scenario, the probability for such a discrimination is even less due to a poor statistics.

   hep-phCPC(2019)·8 citations
10. 10*

    Axion dark matter and the Lattice

    Guy D. Moore🇩🇪

    First I will review the QCD theta problem and the Peccei-Quinn solution, with its new particle, the axion. I will review the possibility of the axion as dark matter. If PQ symmetry was restored at some point in the hot early Universe, it should be possible to make a definite prediction for the axion mass if it constitutes the Dark Matter. I will describe progress on one issue needed to make this prediction -- the dynamics of axionic string-wall networks and how they produce axions. Then I will discuss the sensitivity of the calculation to the high temperature QCD topological susceptibility. My emphasis is on what temperature range is important, and what level of precision is needed.

    hep-phhep-latEPJ Web Conf.(2018)·27 citations
11. 11*

    Pentaquarks with hidden charm as hadroquarkonia

    Michael I. Eides🇺🇸 · Victor Yu. Petrov🇷🇺 · Maxim V. Polyakov🇷🇺

    We consider hidden charm pentaquarks as hadroquarkonium states in a QCD inspired approach. Pentaquarks arise naturally as bound states of quarkonia excitations and ordinary baryons. The LHCb $P_c(4450)$ pentaquark is interpreted as a ${\psi }^{\prime }$-nucleon bound state with spin-parity $J^P=3/2^{-}$. The partial decay width $\Gamma (P_c(4450)\to J/\psi +N)\approx 11$ MeV is calculated and turned out to be in agreement with the experimental data for $P_c(4450)$. The $P_c(4450)$ pentaquark is predicted to be a member of one of the two almost degenerate hidden-charm baryon octets with spin-parities $J^P=1/2^{-},3/2^{-}$. The masses and decay widths of the octet pentaquarks are calculated. The widths are small and comparable with the width of the $P_c(4450)$ pentaquark, and the masses of the octet pentaquarks satisfy the Gell-Mann-Okubo relation. Interpretation of pentaquarks as loosely bound ${\Sigma }_c{\bar{D}}^{\ast }$ and ${\Sigma }_c^{\ast }{\bar{D}}^{\ast }$ deuteronlike states is also considered. We determine quantum numbers of these bound states and calculate their masses in the one-pion exchange scenario. The hadroquarkonium and molecular approaches to exotic hadrons are compared and the relative advantages and drawbacks of each approach are discussed.

    hep-phEPJC(2018)·53 citations
12. 12*

    Hadronic decays of $B\to a_1(1260)b_1(1235)$ in the perturbative QCD approach

    Hao-Yang Jing🇨🇳 · Xin Liu🇨🇳 · Zhen-Jun Xiao🇨🇳

    We calculate the branching ratios and polarization fractions of the $B\to a_1{b}_1$ decays in the perturbative QCD(pQCD) approach at leading order, where $a_1$($b_1$) stands for the axial-vector $a_1(1260)[b_1(1235)]$ state. By combining the phenomenological analyses with the perturbative calculations, we find the following results: (a) the large decay rates around $10^{-5}$ to $10^{-6}$ of the $B\to a_1{b}_1$ decays dominated by the longitudinal polarization(except for the $B^{+}\to b_1^{+}{a}_1^0$ mode) are predicted and basically consistent with those in the QCD factorization(QCDF) within errors, which are expected to be tested by the Large Hadron Collider and Belle-II experiments. The large $B^0\to a_1^0{b}_1^0$ branching ratio could provide hints to help explore the mechanism of the color-suppressed decays. (b) the rather different QCD behaviors between the $a_1$ and $b_1$ mesons result in the destructive(constructive) contributions in the nonfactorizable spectator diagrams with $a_1(b_1)$ emission. Therefore, an interesting pattern of the branching ratios appears for the color-suppressed $B^0\to a_1^0{a}_1^0,a_1^0{b}_1^0,$ and $b_1^0{b}_1^0$ modes in the pQCD approach, $Br(B^0\to b_1^0{b}_1^0)>Br(B^0\to a_1^0{b}_1^0)\gtrsim Br(B^0\to a_1^0{a}_1^0)$, which is different from $Br(B^0\to b_1^0{b}_1^0)\sim Br(B^0\to a_1^0{b}_1^0)\gtrsim Br(B^0\to a_1^0{a}_1^0)$ in the QCDF and would be verified at future experiments. (c) the large naive factorization breaking effects are observed in these $B\to a_1{b}_1$ decays. Specifically, the large nonfactorizable spectator(weak annihilation) amplitudes contribute to the $B^0\to b_1^{+}{a}_1^{-}(B^{+}\to a_1^{+}{b}_1^0\mathrm{and}{B}^{+}\to b_1^{+}{a}_1^0)$ mode(s), which demand confirmations via the precise measurements.

    hep-phPRD(2017)·0 citations
13. 13*

    Higher-order QED effects in hadronic processes

    German F. R. Sborlini🇮🇹

    In this presentation, we describe the computation of higher-order QED effects relevant in hadronic collisions. In particular, we discuss the calculation of mixed QCD-QED one-loop contributions to the Altarelli-Parisi splittings functions, as well as the pure two-loop QED corrections. We explain how to extend the DGLAP equations to deal with new parton distributions, emphasizing the consequences of the novel corrections in the determination (and evolution) of the photon distributions.

    hep-phhep-exPoS(2017)·5 citations
14. 14*

    Would a Deeply Bound $b\bar{b}b\bar{b}$ Tetraquark Meson be Observed at the LHC?

    Estia Eichten🇺🇸 · Zhen Liu🇺🇸

    There has been much theoretical speculation about the existence of a deeply bounded tetra-bottom state. Such a state would not be expected to be more than a GeV below ${\rm Y}{\rm Y}$ threshold. If such a state exists below the ${\eta }_b{\eta }_b$ threshold it would be narrow, as Zweig allowed strong decays are kinematically forbidden. Given the observation of ${\rm Y}$ pair production at CMS, such a state with a large branching fraction into ${\rm Y}{{\rm Y}}^{\ast }$ is likely discoverable at the LHC. The discovery mode is similar to the SM Higgs decaying into four leptons through the $Z{Z}^{\ast }$ channel. The testable features of both production and the four lepton decays of such a tetra-bottom ground state are presented. The assumptions required for each feature are identified, allowing the application of our results more generally to a resonance decaying into four charged leptons (through the ${\rm Y}{{\rm Y}}^{\ast }$ channel) in the same mass region.

    hep-ph29 citations
15. 15*

    Comment on `Note on X(3872) production at hadron colliders and its molecular structure'

    A. Esposito🇺🇸 · B. Grinstein🇺🇸 · L. Maiani🇨🇭 · F. Piccinini🇮🇹 · A. Pilloni🇺🇸 · A.D. Polosa🇮🇹 · V. Riquer🇨🇭

    We briefly comment on the paper by Albaladejo et al. [arXiv:1709.09101], rejecting its conclusions.

    hep-phCPC(2018)·25 citations
16. 16*

    Scalar field dark matter with spontaneous symmetry breaking and the $3.5$ keV line

    Catarina Cosme🇵🇹 · João G. Rosa🇵🇹 · O. Bertolami🇵🇹

    We show that the present dark matter abundance can be accounted for by an oscillating scalar field that acquires both mass and a non-zero expectation value from interactions with the Higgs field. The dark matter scalar field can be sufficiently heavy during inflation, due to a non-minimal coupling to gravity, so as to avoid the generation of large isocurvature modes in the CMB anisotropies spectrum. The field begins oscillating after reheating, behaving as radiation until the electroweak phase transition and afterwards as non-relativistic matter. The scalar field becomes unstable, although sufficiently long-lived to account for dark matter, due to mass mixing with the Higgs boson, decaying mainly into photon pairs for masses below the MeV scale. In particular, for a mass of $\sim 7$ keV, which is effectively the only free parameter, the model predicts a dark matter lifetime compatible with the recent galactic and extragalactic observations of a 3.5 keV X-ray line.

    hep-phastro-ph.COgr-qcPLB(2018)·28 citations
17. 17*

    Invoking Chiral Vector Leptoquark to explain LFU violation in B Decays

    Bhavesh Chauhan🇮🇳 · Bharti Kindra🇮🇳

    LHCb has recently reported more than $2\sigma$ deviation from the Standard Model prediction in the observable $R_{J/\psi }$. We study this anomaly in the framework of a vector leptoquark along with other lepton flavor universality violating measurements which include $R_{K^{(\ast )}}$, and $R_{D^{(\ast )}}$. We show that a chiral vector leptoquark can explain all the aforementioned anomalies consistently while also respecting other experimental constraints.

    hep-ph31 citations
18. 18*

    Primordial Cosmology in Mimetic Born-Infeld Gravity

    Mariam Bouhmadi-López🇪🇸 · Che-Yu Chen🇹🇼 · Pisin Chen🇹🇼

    The Eddington-inspired-Born-Infeld (EiBI) model is reformulated within the mimetic approach. In the presence of a mimetic field, the model contains non-trivial vacuum solutions which could be free of spacetime singularity because of the Born-Infeld nature of the theory. We study a realistic primordial vacuum universe and prove the existence of regular solutions, such as primordial inflationary solutions of de Sitter type or bouncing solutions. Besides, the linear instabilities present in the EiBI model are found to be avoidable for some interesting bouncing solutions in which the physical metric as well as the auxiliary metric are regular at the background level.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2017)·29 citations
19. 19*

    New tracker models of dark energy

    Satadru Bag🇮🇳 · Swagat S. Mishra🇮🇳 · Varun Sahni🇮🇳

    We describe a new class of dark energy (DE) models which behave like cosmological trackers at early times. These models are based on the $\alpha$-attractor set of potentials, originally discussed in the context of inflation. The new models allow the current acceleration of the universe to be reached from a wide class of initial conditions. Prominent examples of this class of models are the potentials $\coth \phi$ and $\cosh \phi$. A remarkable feature of this new class of models is that they lead to large enough negative values of the equation of state at the present epoch, consistent with the observations of accelerated expansion of the universe, from a very large initial basin of attraction. They therefore avoid the fine tuning problem which afflicts many models of DE.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2018)·35 citations
20. 20*

    On the Stability of Infinite Derivative Abelian Higgs

    Anish Ghoshal🇮🇹 · Anupam Mazumdar🇳🇱 · Nobuchika Okada🇺🇸 · Desmond Villalba🇺🇸

    Motivated by the stringy effects by modifying the local kinetic term of an Abelian Higgs field by the Gaussian kinetic term we show that the Higgs field does not possess any instability, the Yukawa coupling between the scalar and the fermion, the gauge coupling, and the self interaction of the Higgs yields exponentially suppressed running at high energies, showing that such class of theory never suffers from vacuum instability. We briefly discuss its implications for the early Universe cosmology.

    ↳ hep-thhep-phPRD(2018)·57 citations
21. 21*

    Deconfinement phase transition in a magnetic field in 2+1 dimensions from holographic models

    Diego M. Rodrigues🇧🇷 · Eduardo Folco Capossoli🇧🇷 · Henrique Boschi-Filho🇧🇷

    Using two different models from holographic quantum chromodynamics (QCD) we study the deconfinement phase transition in $2+1$ dimensions in the presence of a magnetic field. Working in 2+1 dimensions lead us to {\sl exact} solutions on the magnetic field, in contrast with the case of 3+1 dimensions where the solutions on the magnetic field are perturbative. As our main result we predict a critical magnetic field $B_c$ where the deconfinement critical temperature vanishes. For weak fields meaning $B<B_c$ we find that the critical temperature decreases with increasing magnetic field indicating an inverse magnetic catalysis (IMC). On the other hand, for strong magnetic fields $B>B_c$ we find that the critical temperature raises with growing field showing a magnetic catalysis (MC). These results for IMC and MC are in agreement with the literature.

    ↳ hep-thhep-phPLB(2018)·26 citations
22. 22*

    A linear sigma model for multiflavor gauge theories

    Y. Meurice🇺🇸

    We consider a linear sigma model describing $2N_f^2$ bosons ($\sigma$, ${\mathbf{a}}_0$, ${\eta }^{\prime }$ and $\pi$) as an approximate effective theory for a $SU(3)$ local gauge theory with $N_f$ Dirac fermions in the fundamental representation. The model has a renormalizable $U(N_f{)}_L⨂U(N_f{)}_R$ invariant part, which has an approximate $O(2N_f^2)$ symmetry, and two additional terms, one describing the effects of a $SU(N_f{)}_V$ invariant mass term and the other the effects of the axial anomaly. We calculate the spectrum for arbitrary $N_f$. Using preliminary and published lattice results from the LatKMI collaboration, we found combinations of the masses that vary slowly with the explicit chiral symmetry breaking and $N_f$. This suggests that the anomaly term plays a leading role in the mass spectrum and that simple formulas such as $M_{\sigma }^2\simeq (2/N_f-C_{\sigma })M_{{\eta }^{\prime }}^2$ should apply in the chiral limit. Lattice measurements of $M_{{\eta }^{\prime }}^2$ and of approximate constants such as $C_{\sigma }$ could help locating the boundary of the conformal window. We show that our calculation can be adapted for arbitrary representations of the gauge group and in particular to the minimal model with two sextets, where similar patterns are likely to apply.

    ↳ hep-lathep-phhep-thPRD(2017)·19 citations
23. 23*

    Current matrix element in HAL QCD's wave function equivalent potential method

    Kai Watanabe🇯🇵 · Noriyoshi Ishii🇯🇵

    We give a formula to calculate a matrix element of a conserved current in the effective quantum mechanics defined by the wave function equivalent potentials proposed by HAL QCD collaboration. As a first step, a non-relativistic field theory with two channel coupling is considered as the original theory, with which a wave function equivalent HAL QCD potential is obtained in a closed analytic form. The external field method is used to derive the formula by demanding that the result should agree with the original theory. With this formula, the matrix element is obtained by sandwiching the effective current operator between the left and the right eigen functions of the effective Hamiltonian associated with the HAL QCD potential. In addition to the naive one-body current, the effective current operator contains an additional two-body term emerging from the degrees of freedom which has been integrated out.

    ↳ hep-lathep-phnucl-thPTEP(2018)·1 citation
24. 24*

    Perturbative width of open rigid strings

    A. S. Bakry🇨🇳 · M. A. Deliyergiyev🇨🇳 · A. Galal🇨🇳 · M. N. Khalil🇩🇪

    We present perturbative calculation of the width of the energy profile of rigid strings up to two loops in D dimensions. The perturbative expansion of the extrinsic curvature term signifying the rigidity/smoothness of the string in Polyakov-Kleinert action is taken around the free Nambu-Goto string. The mean-square width of the string field is derived for open strings with Dirichlet boundary condition. We compare the broadening of the smooth Polyakov-Kleinert string to the lattice Mont-Carlo data of the QCD flux tube just before the deconfinement point and find a good match at the intermediate and large color source separation.

    ↳ hep-thhep-lathep-phPRD(2022)·7 citations
25. 25*

    Topological Inflation

    Andrey O. Barvinsky🇷🇺 · Ariel R. Zhitnitsky🇨🇦

    We discuss a novel scenario for early cosmology, when the inflationary quasi-de Sitter phase dynamically originates from the initial quantum state represented by the microcanonical density matrix. This genuine quantum effect occurs as a result of the dynamics of the topologically nontrivial sectors in a (conjectured) strongly coupled QCD-like gauge theory in expanding universe. The crucial element of our proposal is the presence in our framework of a nontrivial ${\mathbb{S}}^1$ which plays the dual role in construction: it defines the periodic gravitational instanton (on the gravity side) and it also defines a nontrivial gauge holonomy (on the gauge side) generating the vacuum energy. The effect is global in nature and cannot be formulated in terms of a gradient expansion in an effective local field theory. We also discuss a graceful exit from holonomy inflation due to the helical instability. The number of e-folds in the holonomy inflation framework is determined by the gauge coupling constant at the moment of inflation, and estimated as $N_{\mathrm{infl}}\sim {\alpha }^{-2}(H_0)\sim 10^2$. We also comment on the relation of our framework with the no-boundary and tunneling cosmological proposals and their recent criticism.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2018)·16 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.