Tue·Jan 30, 2018Tuesday·January 30, 2018

1. 01*

   Determination of $J/\psi$ chromoelectric polarizability from lattice data

   Maxim V. Polyakov🇷🇺 · Peter Schweitzer🇺🇸

   The chromoelectric polarizability of $J/\psi$ is extracted from lattice QCD data on the nucleon-$J/\psi$ potential in the heavy quark limit. The value of $\alpha (1S)=(1.6\pm 0.8){\mathrm{GeV}}^{-3}$ is obtained. We also comment on the possibility of hadrocharmonia.

   hep-phPRD(2018)·21 citations
2. 02*

   Toward Initial Conditions of Conserved Charges Part I: Spatial Correlations of Quarks and Antiquarks

   M. Martinez🇺🇸 · Matthew D. Sievert🇺🇸 · Douglas E. Wertepny🇪🇸

   In this paper, we study the spatial correlations among quarks and antiquarks produced at mid-rapidity by gluon pair production in the color glass condensate framework. This paper is the first part of a series in which we calculate a complete set of quark/quark, quark/antiquark, and antiquark/antiquark spatial correlation functions in heavy-light ion collisions, with the goal of incorporating their conserved charges into the initial conditions of hydrodynamics. The physical mechanisms captured in this calculation include geometric, entanglement, and interaction-mediated correlations. In this first paper, we construct the building blocks for the correlations arising from single- and double-pair production, studying in detail the single-pair case and the general features of the double-pair case. We find a rich correlation structure in transverse coordinate space, with different mechanisms dominating over different length scales, and we present explicit results for the quark-antiquark correlations in the single-pair production regime. We reserve a detailed discussion of the double-pair production regime for the next paper in this sequence.

   hep-phnucl-thJHEP(2018)·20 citations
3. 03*

   Charmonia Production in $W\to (c\bar{c})D_s^{(\ast )}$ Decays

   A. V. Luchinsky🇷🇺

   In the presented paper production of charmonium state $\mathcal{Q}$ in exclusive $W\to \mathcal{Q}{D}_s^{(\ast )}$ decays is analyzed in the framework of both leading order Nonrelativistic Quantum Chromodynamics (NRQCD) and light-cone expansion (LC) models. Analytical and numerical predictions for the branching fractions of these decays in both approaches are given. The typical value of the branching fractions is $\sim 10^{-11}$ and it turns out the LC results are about 4 times lager than NRQCD ones, so the effect of internal quark should be taken into account. Some estimates of color-octet contributions are presented and it is shown, that these contributions could be comparable with color-singlet results.

   hep-ph1 citation
4. 04*

   Radiative decays of light-quark mesons to a pion revisited in the covariant oscillator quark model

   Kenji Yamada🇯🇵 · Tomohito Maeda🇯🇵

   The present talk consists of two parts. The first one is allocated for consideration of the dimension of bilocal meson fields for quark-antiquark meson systems, which have been so far treated as the bosonic fields independent of constituent quark flavors, in the covariant oscillator quark model. Revisiting the electromagnetic currents of quark-antiquark meson systems, we show that the bilocal meson fields should be bosonic for light-quark meson systems, while fermionic for heavy-light and heavy-heavy meson systems. In the second part we apply the effective electromagnetic interactions of meson systems derived in the first part to radiative decay processes for the excited states of light-quark mesons. The calculated results for the $\pi \gamma$ decay widths of the $a_1(1260)$, $a_2(1320)$, $b_1(1235)$ and ${\pi }_2(1670)$ mesons are in fair agreement with experiment, except for the $b_1(1235)$ meson. As for the $\rho (770{)}^0\gamma$ decay width of the $f_1(1285)$ the present model strongly supports the experimental results in 1995 and 2016, respectively, of VES and CLAS Collaborations, not the average value by the Particle Data Group.

   hep-phPoS(2018)·0 citations
5. 05*

   Simple Standard Model Extension by Heavy Charged Scalar

   Edward Boos🇷🇺 · Igor Volobuev🇷🇺

   We consider a Standard Model extension by a heavy charged scalar gauged only under the $U_Y(1)$ weak hypercharge gauge group. Such an extension, being gauge invariant with respect to the SM gauge group, is a simple special case of the well known Zee model. Since the interactions of the charged scalar with the Standard Model fermions turn out to be significantly suppressed compared to the Standard Model interactions, the charged scalar provides an example of a long-lived charged particle being interesting to search for at the LHC. We present the pair and single production cross sections of the charged scalar at different colliders and the possible decay widths for various boson masses. It is shown that the current ATLAS and CMS searches at 8 and 13 TeV collision energy lead to the bounds on the scalar boson mass of about 300--320 GeV. The limits are expected to be much larger for higher collision energies and, assuming $15a{b}^{-1}$ integrated luminosity, reach about 2.7 TeV at future 27 TeV LHC thus covering the most interesting mass region.

   hep-phPRD(2018)·6 citations
6. 06*

   0+ and 1+ heavy-light exotic mesons at N2LO in the chiral limit

   R.M Albuquerque (FAT, UERJ, Rio de Janeiro-BR)🇧🇷 · S. Narison (LUPM-CNRS, Montpellier-FR)🇫🇷 · F. Fanomezana🇲🇬 · A. Rabemananjara🇲🇬 · D. Rabetiarivony🇲🇬 · G. Randriamanatrika (iHEPMAD, Antananarivo-MG)🇲🇬

   We use QCD spectral sum rules (QSSR) and the factorization properties of molecule and four-quark currents to estimate the masses and couplings of the 0+ and 1+ molecules and four-quark at N2LO of PT QCD. We include in the OPE the contributions of non-perturbative condensates up to dimension-six. Within the Laplace sum rules approach (LSR) and in the MS-scheme, we summarize our results in Table 2, which agree within the errors with some of the observed XZ-like molecules or/and four-quark. Couplings of these states to the currents are also extracted. Our results are improvements of the LO ones in the existing literature.

   hep-phhep-exhep-lat1 citation
7. 07*

   A Minimal Model For Two-Component FIMP Dark Matter: A Basic Search

   S. Peyman Zakeri🇮🇷 · S. Mohammad Moosavi Nejad🇮🇷 · Mohammadreza Zakeri🇺🇸 · S. Yaser Ayazi🇮🇷

   In the multi-component configurations of dark matter phenomenology, we propose a minimal two-component configuration which is an extension of the Standard Model with only three new fields; one scalar and one fermion interact with the thermal soup through Higgs portal, mediated by the other scalar in such a way that the stabilities of dark matter candidates are made simultaneously by an explicit $Z_2$ symmetry. Against the most common freeze-out framework, we look for dark matter particle signatures in the freeze-in scenario by evaluating the relic density and detection signals. A simple distinguishing feature of the model is the lack of dark matter conversion, so the dark matter components act individually and the model can be adapted entirely to both singlet scalar and singlet fermionic models, separately. We find dark matter self-interaction as the most promising approach to probe such feeble models. Although the scalar component satisfies this constraint, the fermionic one refuses it even in the resonant region.

   hep-phCPC(2018)·27 citations
8. 08*

   Universality of Generalized Parton Distributions in Light-Front Holographic QCD

   Guy F. de Teramond🇨🇷 · Tianbo Liu🇺🇸 · Raza Sabbir Sufian🇺🇸 · Hans Gunter Dosch🇩🇪 · Stanley J. Brodsky🇺🇸 · Alexandre Deur (HLFHS Collaboration)🇺🇸

   The structure of generalized parton distributions is determined from light-front holographic QCD up to a universal reparametrization function $w(x)$ which incorporates Regge behavior at small $x$ and inclusive counting rules at $x\to 1$. A simple ansatz for $w(x)$ which fulfills these physics constraints with a single-parameter results in precise descriptions of both the nucleon and the pion quark distribution functions in comparison with global fits. The analytic structure of the amplitudes leads to a connection with the Veneziano model and hence to a nontrivial connection with Regge theory and the hadron spectrum.

   hep-phhep-exhep-lathep-th+1PRL(2018)·174 citations
9. 09*

   Nucleon Properties in the Polyakov Quark Meson Model

   Yingying Li🇨🇳 · Jinniu Hu🇨🇳 · Hong Mao🇨🇳

   We study the nucleon as a nontopological soliton in a quark medium as well as in a nucleon medium in terms of the Polyakov quark meson (PQM) model with two flavors at finite temperature and density. The constituent quark masses evolving with the temperature at various baryon chemical potentials are calculated and the equations of motion are solved according to the proper boundary conditions. The PQM model predicts an increasing size of the nucleon and a reduction of the nucleon mass in both hot environment. However, the phase structure is different from each other in quark and nucleon mediums. There is a crossover in the low-density region and a first-order phase transition in the high-density region in quark medium, whereas there exists a crossover characterized by the overlap of the nucleons in nucleon medium.

   hep-phPRC(2018)·5 citations
10. 10*

    The kurtosis of net baryon number fluctuations from a realistic Polyakov--Nambu--Jona-Lasinio model along the experimental freeze-out line

    Zhibin Li🇨🇳 · Kun Xu🇨🇳 · Xinyang Wang🇨🇳 · Mei Huang🇨🇳

    Firstly we qualitatively analyze the formation of the dip and peak structures of the kurtosis $\kappa {\sigma }^2$ of net baryon number fluctuation along imagined freeze-out lines and discuss the signature of the existence of the QCD critical end point (CEP) in the Nambu--Jona-Lasinio (NJL) model, Polyakov-NJL (PNJL) model as well as $\mu$-dependent PNJL($\mu$ PNJL) model with different parameter sets, and then we apply a realistic PNJL model with parameters fixed by lattice data at zero chemical potential, and quantitatively investigate its $\kappa {\sigma }^2$ along the real freeze-out line extracted from experiments. The important contribution from gluodynamics to the baryon number fluctuations is discussed. The peak structure of $\kappa {\sigma }^2$ along the freeze-out line is solely determined by the existence of the CEP mountain and can be used as a clean signature for the existence of CEP. The formation of the dip structure is sensitive to the relation between the freeze-out line and the phase boundary, and the freeze-out line starts from the back-ridge of the phase boundary is required. To our surprise, the kurtosis $\kappa {\sigma }^2$ produced from the realistic PNJL model along the experimental freeze-out line agrees with BES-I data well, which indicates that equilibrium result can explain the experimental data. It is worth to point out that the extracted freeze-out temperatures from beam energy scan measurement are indeed higher than the critical temperatures at small chemical potentials, which supports our qualitative analysis.

    hep-phhep-thEPJC(2019)·67 citations
11. 11*

    Angular momentum and parity of a two gluon system

    V. Pleitez🇧🇷

    In this work we obtain all the allowed values of the angular momentum and parity for two massless non-Abelian fields. In particular, we show that, unlike the two photons system, two gluons can be in a state with $J^P=1^{\pm }$, $(2k{)}^{-}$, and $(2k+1{)}^{-}$, $k\ge 1$. This is a general result since it was obtained using only the laws of addition of the angular momentum.

    hep-phhep-exhep-th3 citations
12. 12*

    Asymmetric dark matter, baryon asymmetry and lepton number violation

    Mads T. Frandsen🇩🇰 · Claudia Hagedorn🇩🇰 · Wei-Chih Huang🇩🇰 · Emiliano Molinaro🇩🇰 · Heinrich Päs🇩🇪

    We study the effect of lepton number violation (LNV) on baryon asymmetry, generated in the early Universe, in the presence of a dark sector with a global symmetry $U(1{)}_X$, featuring asymmetric dark matter (ADM). We show that in general LNV, observable at the LHC or in neutrinoless double beta decay experiments, cannot wash out a baryon asymmetry generated at higher scales, unlike in scenarios without such dark sector. An observation of LNV at the TeV scale may thus support ADM scenarios. Considering several models with different types of dark matter (DM), we find that the DM mass is of the order of a few GeV or below in our scenario.

    hep-phhep-exPLB(2018)·8 citations
13. 13*

    $S_4$ symmetric four-generation models for charged leptons

    Teruyuki Kitabayashi · Hirona Matsumura · Kantaro Minakuchi · Hiroshi Ozaki

    We propose $S_4$ symmetric four-generation models for charged leptons. Although an $S_4$ symmetric four-generation model has been already proposed, there are some additional symmetries in the model. We construct four-generation models for charged leptons with only requirement of exact $S_4$ symmetry. It turned out that at least one of the models is consistent with observations of charged lepton masses and predicts the mass of the charged lepton of the fourth generation to be 556 GeV.

    hep-ph0 citations
14. 14*

    Proposal to look for the anomalous isotopic symmetry breaking in central diffractive production of the $f_1(1285)$ and $a_0^0(980)$ resonances at the LHC

    N.N. Achasov🇷🇺 · G.N. Shestakov🇷🇺

    At very high energies, and in the central region ($x_F\simeq 0$), the double-Pomeron exchange mechanism gives the dominant contribution to the production of hadrons with the positive $C$ parity and isospin $I=0$. Therefore, the observation of resonances in the states with $I=1$ will be indicative of their production or decay with the isotopic symmetry breaking. Here, we bear in mind the cases of the anomalous breaking of the isotopic symmetry, i.e., when the cross section of the process breaking the isospin is not of the order of $10^{-4}$ of the cross section of the allowed process but of the order of $1\%$. The paper draws attention to the reactions $pp\to p(f_1(1285)/f_1(1420))p\to p({\pi }^{+}{\pi }^{-}{\pi }^0)p$ and $pp\to p(K\bar{K})p\to p(a_0^0(980))p\to p(\eta {\pi }^0)p$ in which a similar situation can be realized, owing to the $K\bar{K}$ loop mechanisms of the breaking of isotopic symmetry. We note that there is no visible background in the ${\pi }^{+}{\pi }^{-}{\pi }^0$ and $\eta {\pi }^0$ channels. Observation of the process $pp\to p(f_1(1285))p\to p({\pi }^{+}{\pi }^{-}{\pi }^0)p$ would be a confirmation of the first results from the VES and BESIII detectors, indicating the very large isospin breaking in the decay $f_1(1285))\to {\pi }^{+}{\pi }^{-}{\pi }^0$.

    hep-phhep-exnucl-thPRD(2018)·5 citations
15. 15*

    Flavorful leptoquarks at hadron colliders

    Gudrun Hiller🇩🇪 · Dennis Loose🇩🇪 · Ivan Nisandzic🇩🇪

    $B$-physics data and flavor symmetries suggest that leptoquarks can have masses as low as few $\mathcal{O}(\text{mbox}TeV)$, predominantly decay to third generation quarks, and highlight $pp\to b\mu \mu$ signatures from single production and $pp\to bb\mu \mu$ from pair production. Abandoning flavor symmetries could allow for inverted quark hierarchies, and cause sizable $pp\to j\mu \mu$ and $jj\mu \mu$ cross sections, induced by second generation couplings. Final states with leptons other than muons including lepton flavor violation (LFV) ones can also arise. The corresponding couplings can also be probed by precision studies of the $B\to (X_s,K^{\ast },\varphi )ee$ distribution and LFV searches in $B$-decays. We demonstrate sensitivity in single leptoquark production for the LHC and extrapolate to the high luminosity HL-LHC. Exploration of the bulk of the phase space requires a hadron collider beyond the reach of the LHC, with $b$-identification capabilities.

    hep-phhep-exPRD(2018)·71 citations
16. 16*

    New feature of low $p_T$ charm quark hadronization in $pp$ collisions at $\sqrt{s}=7$ TeV

    Jun Song🇨🇳 · Hai-hong Li🇨🇳 · Feng-lan Shao🇨🇳

    Treating the light-flavor constituent quarks and antiquarks that can well describe the data of light-flavor hadrons in $pp$ collisions at $\sqrt{s}=7$ TeV as the underlying source of chromatically neutralizing the charm quarks of low transverse momenta ($p_T$), we show that the experimental data of $p_T$ spectra of single-charm hadrons $D^{0,+}$, $D^{\ast +}$ $D_s^{+}$, ${\Lambda }_c^{+}$ and ${\Xi }_c^0$ at mid-rapidity in the low $p_T$ range ($2\lesssim p_T\lesssim 7$ GeV/$c$) in $pp$ collisions at $\sqrt{s}=7$ TeV can be well understood by the equal-velocity combination of perturbatively-created charm quarks and those light-flavor constituent quarks and antiquarks. This suggests a possible new scenario of low $p_T$ charm quark hadronization, in contrast to the traditional fragmentation mechanism, in $pp$ collisions at LHC energies. This is also another support for the exhibition of the effective constituent quark degrees of freedom for the small parton system created in $pp$ collisions at LHC energies.

    hep-phEPJC(2018)·87 citations
17. 17*

    Mass spectra of singly heavy baryons in a self-consistent chiral quark-soliton model

    June-Young Kim🇰🇷 · Hyun-Chul Kim🇰🇷 · Ghil-Seok Yang🇰🇷

    We investigate the mass spectra of the lowest-lying singly heavy baryons, based on the self-consistent chiral quark-soliton model. We take into account the rotational $1/N_c$ and strange current quark mass ($m_{\mathrm{s}}$) corrections. Regarding $m_{\mathrm{s}}$ as a small perturbation, we expand the effective chiral action to the second order with respect to $m_s$. The mass spectra of heavy baryons are computed and compared with the experimental data. Fitting the classical masses of the heavy baryon to the center mass of each representation, we determine the masses of all the lowest-lying singly heavy baryons. We predict the mass of the ${\Omega }_b^{\ast }$ baryon to be 6081.9 MeV, when the second-order $m_{\mathrm{s}}$ corrections are included.

    hep-phhep-exPRD(2018)·35 citations
18. 18*

    Masses and sigma terms of doubly charmed baryons up to $\mathcal{O}(p^4)$ in manifestly Lorentz-invariant baryon chiral perturbation theory

    De-Liang Yao🇪🇸

    We calculate the masses and sigma terms of the doubly charmed baryons up to next-to-next-to-next-to-leading order (i.e., $\mathcal{O}(p^4)$) in a covariant baryon chiral perturbation theory by using the extended-on-mass-shell renormalization scheme. Their expressions both in infinite and finite volumes are provided for chiral extrapolation in lattice QCD. As a first application, our chiral results of the masses are confronted with the existing lattice QCD data in the presence of finite volume corrections. Up to $\mathcal{O}(p^3)$ all relevant low energy constants can be well determined. As a consequence, we obtain the physical values for the masses of ${\Xi }_{cc}$ and ${\Omega }_{cc}$ baryons by extrapolating to the physical limit. Our determination of the ${\Xi }_{cc}$ mass is consistent with the recent experimental value by LHCb collaboration, however, larger than the one by SELEX collaboration. In addition, we predict the pion-baryon and strangeness-baryon sigma terms, as well as the mass splitting between the ${\Xi }_{cc}$ and ${\Omega }_{cc}$ states. Their quark mass dependences are also discussed. The numerical procedure can be applied to the chiral results of $\mathcal{O}(p^4)$ order, where more unknown constants are involved, when more data are available for unphysical pion masses.

    hep-phPRD(2018)·45 citations
19. 19*

    HDECAY: Twenty++ Years After

    Abdelhak Djouadi🇫🇷 · Jan Kalinowski🇵🇱 · Margarete Muehlleitner🇩🇪 · Michael Spira🇨🇭

    The program HDECAY determines the partial decay widths and branching ratios of the Higgs bosons within the Standard Model with three and four generations of fermions, including the case when the Higgs couplings are rescaled, a general two--Higgs doublet model where the Higgs sector is extended and incorporates five physical states and its most studied incarnation, the minimal supersymmetric Standard Model (MSSM). The program addresses all decay channels including the dominant higher-order effects such as radiative corrections and multi-body channels. Since the first launch of the program, more than twenty years ago, important aspects and new ingredients have been incorporated. In this update of the program description, some of the developments are summarized while others are discussed in some detail.

    hep-phComput.Phys.Commun.(2019)·242 citations
20. 20*

    Constraints from Heavy Higgs boson masses in the two Higgs doublet model

    Jin-Hwan Cho🇰🇷 · Tae Young Kim🇰🇷 · Jeonghyeon Song🇰🇷

    Upon the absence of signals of new physics at the LHC, a reasonable strategy is to assume that new particles are very heavy and the other model parameters are unknown yet. In the aligned two Higgs doublet model, however, heavy Higgs boson masses above 500 GeV enhance some couplings in the scalar potential, which causes a breakdown of the perturbative unitariry in general. Some tuning among model parameters is required. We find that one information on the heavy Higgs boson mass, say $M_H$, has significant theoretical implications: (i) the other heavy Higgs bosons should have similar masses to $M_H$ within $\pm \mathcal{O}(10)\%$; (ii) the inequalities from the theoretical constraints are practically reduced to an equation such that $m_{12}^2\tan \beta$ is constant, where $m_{12}^2$ is the soft $Z_2$ breaking parameter and $\tan \beta$ is the ratio of two vacuum expectation values; (iii) the triple Higgs coupling ${\lambda }_{HHh}$ is constant over $\tan \beta$ while ${\lambda }_{HHH}$ and ${\lambda }_{AAH}$ are linearly proportional to $\tan \beta$. The double Higgs-strahlung process of $e^{+}{e}^{-}\to ZHH$ is also studied, of which the total cross section is almost constant with the given $M_H$.

    hep-phJ.Korean Phys.Soc.(2018)·1 citation
21. 21*

    A Simple Expression for Heavy to Light Meson Semileptonic Decays Form Factors

    T. N. Pham🇫🇷

    Like the two-photon and two-gluon decays of the $P$-wave ${\chi }_{c0,2}$ and ${\chi }_{b0,2}$ charmonium state for which the Born term produces a very simple decgays amplitude in terms of an effective Lagrangian with two-quark local operator, the Born term for the processes $c\bar{d}\to (\pi ,K)\ell \nu$ and $b\bar{d}\to (\pi ,K)\ell \nu$, could also produce the $D$ and $B$ meson semileptonic decays with the light meson $\pi ,K$ in the final state. In this approach to heavy-light meson form factors with the $\pi$, K meson treated as Goldstone boson, a simple expression is found for the decays form factors, given as~: $f_{+}(0)/(1-q^2/(m_H^2+m_{\pi }^2))$, with $H=D,B$ for $D,B\to \pi$ form factors, and $f_{+}(0)/(1-q^2/(m_H^2+m_K^2))$ for $B,D\to K$ form factor. The purpose of this paper is to show that this expression for the form factors could describe rather well the $q^2$- behaviour observed in the BaBar, Belle and BESIII measurements and lattice simulation. In particular, the $D\to K$ form factors are in good agreement with the measured values in the whole range of $q^2$ showing evidence for $SU(3)$ breaking with the presence of $m_K^2$ term in the quark propagator, but some corrections to the Born term are needed at large $q^2$ for $D,B\to \pi$ form factors.

    hep-phhep-exInt.J.Mod.Phys.A(2018)·3 citations
22. 22*

    Strange Axial-vector Mesons in D Meson Decays

    Peng-Fei Guo🇨🇳 · Di Wang🇨🇳 · Fu-Sheng Yu🇨🇳

    The nature of strange axial-vector mesons are not well understood and can be investigated in $D$ meson decays. In this work, it is found that the experimental data of $D^0\to K^{\pm }{K}_1^{\mp }(1270)(\to \rho K\text{or}{K}^{\ast }\pi )$ in the $D^0\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ mode, disagree with the equality relation under the narrow width approximation and $CP$ conservation of strong decays. Considering more other results of $K_1(1270)$ decays, the data of $\mathcal{B}(D^0\to K^{-}{K}_1^{+}(1270)(\to K^{\ast 0}{\pi }^{+}))$ is probably overestimated by one order of magnitude. We then calculate the branching fractions of the corresponding processes with $K_1(1400)$ in the factorization approach, and find $\mathcal{B}(D^0\to K^{-}{K}_1^{+}(1400)(\to K^{\ast 0}{\pi }^{+}))$ is comparable to the predicted $\mathcal{B}(D^0\to K^{-}{K}_1^{+}(1270)(\to K^{\ast 0}{\pi }^{+}))$ using the equality relation. Besides, we suggest to measure the ratios between $K_1(1270)\to \rho K$ and $K^{\ast }\pi$ or to test the equality relations in other $D$ meson decay modes.

    hep-phhep-exNucl.Phys.Rev.(2019)·15 citations
23. 23*

    Theoretical Aspects of the Quantum Neutrino

    Stephen Parke🇺🇸

    In this summary of my talk I will review the following the following three theoretical aspects of the quantum neutrino: current status, why we need precision measurements and neutrino oscillations amplitudes.

    hep-phhep-ex9 citations
24. 24*

    Transverse Momentum Resummation for $t$-channel single top quark production at the LHC

    Qing-Hong Cao🇨🇳 · Peng Sun🇨🇳 · Bin Yan🇺🇸 · C.-P. Yuan🇺🇸 · Feng Yuan🇺🇸

    We study the effect of multiple soft gluon radiation on the kinematical distributions of the $t$-channel single top quark production at the LHC. By applying the transverse momentum dependent factorization formalism, large logarithms (of the ratio of large invariant mass $Q$ and small total transverse momentum $q_{\perp }$ of the single-top plus one-jet final state system) are resummed to all orders in the expansion of the strong interaction coupling at the accuracy of next-to-leading logarithm, including the complete next-to-leading order corrections. We show that the main difference from PYTHIA prediction lies on the inclusion of the exact color coherence effect between the initial and final states in our resummation calculation, which becomes more important when the final state jet is required to be in the forward region. We further propose a new experimental observable ${\varphi }^{\ast }$ to test the effect of multiple gluon radiation in the single-top events. The effect of bottom quark mass is also discussed.

    hep-phhep-exPRD(2018)·20 citations
25. 25*

    Prospects for direct searches for light Higgs bosons at the ILC with 250 GeV

    P. Drechsel🇩🇪 · G. Moortgat-Pick🇩🇪 · G. Weiglein🇩🇪

    The particle discovered in the Higgs boson searches at the LHC with a mass of about 125 GeV is compatible within the present uncertainties with the Higgs boson predicted in the Standard Model (SM), but it could also be identified with one of the neutral Higgs bosons in a variety of Beyond the SM (BSM) theories with an extended Higgs sector. The possibility that an additional Higgs boson (or even more than one) could be lighter than the state that has been detected at 125 GeV occurs generically in many BSM models and has some support from slight excesses that were observed above the background expectations in Higgs searches at LEP and at the LHC. The couplings between additional Higgs fields and the electroweak gauge bosons in BSM theories could be probed by model-independent Higgs searches at lepton colliders. We present a generator-level extrapolation of the limits obtained at LEP to the case of a future $e^{+}{e}^{-}$ collider, both for the search where the light Higgs boson decays into a pair of bottom quarks and for the decay-mode-independent search utilising the recoil method. We find that at the ILC with a c.m. energy of 250 GeV, an integrated luminosity of 500 fb^{-1} and polarised beams, the sensitivity to a light Higgs boson with reduced couplings to gauge bosons is improved by more than an order of magnitude compared to the LEP limits and goes much beyond the projected indirect sensitivity of the HL-LHC with 3000 fb^{-1} from the rate measurements of the detected state at 125 GeV.

    hep-phhep-exEPJC(2020)·55 citations
26. 26*

    Reconstructing particle masses in events with displaced vertices

    Giovanna Cottin🇹🇼

    We propose a simple way to extract particle masses given a displaced vertex signature in event topologies where two long-lived mother particles decay to visible particles and an invisible daughter. The mother could be either charged or neutral and the neutral daughter could correspond to a dark matter particle in different models. The method allows to extract the parent and daughter masses by using on-shell conditions and energy-momentum conservation, in addition to the displaced decay positions of the parents, which allows to solve the kinematic equations fully on an event-by-event basis. We show the validity of the method by means of simulations including detector effects. If displaced events are seen in discovery searches at the Large Hadron Collider (LHC), this technique can be applied.

    hep-phhep-exJHEP(2018)·9 citations
27. 27*

    Double-Higgs boson production in the high-energy limit: planar master integrals

    Joshua Davies🇩🇪 · Go Mishima🇩🇪 · Matthias Steinhauser🇩🇪 · David Wellmann🇩🇪

    We consider the virtual corrections to the process $gg\to HH$ at NLO in the high energy limit and compute the corresponding planar master integrals in an expansion for small top quark mass. We provide details on the evaluation of the boundary conditions and present analytic results expressed in terms of harmonic polylogarithms.

    hep-phJHEP(2018)·81 citations
28. 28*

    Heavy flavour in high-energy nuclear collisions: theory overview of transport calculations

    Andrea Beraudo🇮🇹

    Transport calculations are the tool to study medium modifications of heavy-flavour particle distributions in high-energy nuclear collisions. We give a brief overview on their state-of-the art, on the information one can extract, on the questions remaining open and on further analysis to carry out in the near future.

    hep-phnucl-exnucl-thFrascati Phys.Ser.(2017)·0 citations
29. 29*

    Quark-hadron phase structure of QCD matter from SU($4$) Polyakov linear sigma model

    Abdel Magied Abdel Aal Diab🇪🇬 · Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo & WLCAPP, Cairo)🇪🇬

    The SU(4) Polyakov linear sigma model (PLSM) is extended towards characterizing the chiral condensates, ${\sigma }_l$, ${\sigma }_s$ and ${\sigma }_c$ of light, strange and charm quarks, respectively and the deconfinement order-parameters $\varphi$ and $\bar{\varphi }$ at finite temperatures and densities (chemical potentials). The PLSM is considered to study the QCD equation of state in the presence of the chiral condensate of charm for different finite chemical potentials. The PLSM results are in a good agreement with the recent lattice QCD simulations. We conclude that, the charm condensate is likely not affected by the QCD phase-transition, where the corresponding critical temperature is greater than that of the light and strange quark condensates.

    hep-phEPJ Web Conf.(2018)·10 citations
30. 30*

    J/psi with large pT probing the early stage of relativistic heavy ion collisions

    Li Guansong (Tianjin U) · Li Yuhuan (Tianjin U) · Shi Wei (Tianjin U)

    We study the charmonium suppression in different evolutions of quark gluon plasma (QGP) based on the transport model. In the colliding energies of Large Hadron Collider, charmonium final yields are dominated by the recombination of charm and anti-charm quarks in the deconfined phase. Heavy quark diffusions depend less on the shear viscosity of the bulk medium, which makes the J/psi nuclear modification factor in the entire pT bin shows weak dependence on the shear viscosity of QGP. However, charmonium with high transverse momentum pT, can only be produced in the early stage of nuclear collisions, and is sensitive to the initial energy density (or temperature) of QGP, and can be a probe of the initial dynamical evolutions of quark gluon plasma.

    ↳ nucl-thhep-ph0 citations
31. 31*

    Primordial black holes and associated gravitational waves in axion monodromy inflation

    Shu-Lin Cheng🇹🇼 · Wolung Lee🇹🇼 · Kin-Wang Ng🇹🇼

    In the axion monodromy inflation, the inflation is driven by the axion with super-Planckian field values in a monomial potential with superimposed sinusoidal modulations. The coupling of the axion to massless gauge fields can induce copious particle production during inflation, resulting in large non-Gaussian curvature perturbation that leads to the formation of primordial black holes. In this paper, we explore the parameter space in the axion monodromy inflation model that favors the formation of primordial black holes with masses ranging from $10^8$ grams to $20$ solar masses. We also study the associated gravitational waves and their detection in pulsar timing arrays and interferometry experiments.

    ↳ astro-ph.COhep-phhep-thJCAP(2018)·116 citations
32. 32*

    Dyson-Schwinger equation constraints on the gluon propagator in BRST quantised QCD

    Peter Lowdon🇺🇸

    The gluon propagator plays a central role in determining the dynamics of QCD. In this work we demonstrate for BRST quantised QCD that the Dyson-Schwinger equation imposes significant analytic constraints on the structure of this propagator. In particular, we find that these constraints control the appearance of massless components in the gluon spectral density.

    ↳ hep-thhep-phPLB(2018)·20 citations
33. 33*

    Dissipative dark matter halos: The steady state solution II

    R. Foot🇦🇺

    Within the mirror dark matter model and dissipative dark matter models in general, halos around galaxies with active star formation (including spirals and gas rich dwarfs) are dynamical: they expand and contract in response to heating and cooling processes. Ordinary Type II supernovae (SN) can provide the dominant heat source, possible if kinetic mixing interaction exists with strength $ϵ\sim 10^{-9}-10^{-10}$. Dissipative dark matter halos can be modelled as a fluid governed by Euler's equations. Around sufficiently isolated and unperturbed galaxies the halo can relax to a steady state configuration, where heating and cooling rates locally balance and hydrostatic equilibrium prevails. These steady state conditions can be solved to derive the physical properties, including the halo density and temperature profiles, for model galaxies. Here, we have considered idealized spherically symmetric galaxies within the mirror dark particle model, as in the earlier paper [paper I, arXiv:1707.02528], but we have assumed that the local halo heating in the SN vicinity dominates over radiative sources. With this assumption, physically interesting steady state solutions arise which we compute for a representative range of model galaxies. The end result is a rather simple description of the dark matter halo around idealized spherically symmetric systems, characterized in principle by only one parameter, with physical properties that closely resemble the empirical properties of disk galaxies.

    ↳ astro-ph.GAhep-phPRD(2018)·19 citations
34. 34*

    Light nuclei production as a probe of the QCD phase diagram

    Kai-Jia Sun🇨🇳 · Lie-Wen Chen🇨🇳 · Che Ming Ko🇺🇸 · Jie Pu🇨🇳 · Zhangbu Xu🇺🇸

    It is generally believed that the quark-hadron transition at small values of baryon chemical potentials ${\mu }_B$ is a crossover but changes to a first-order phase transition with an associated critical endpoint (CEP) as ${\mu }_B$ increases. Such a ${\mu }_B$-dependent quark-hadron transition is expected to result in a double-peak structure in the collision energy dependence of the baryon density fluctuation in heavy-ion collisions with one at lower energy due to the spinodal instability during the first-order phase transition and another at higher energy due to the critical fluctuations in the vicinity of the CEP. By analyzing the data on the $p$, d and ${}^3$H yields in central heavy-ion collisions within the coalescence model for light nuclei production, we find that the relative neutron density fluctuation $\Delta {\rho }_n=⟨(\delta {\rho }_n{)}^2⟩/⟨{\rho }_n{⟩}^2$ at kinetic freeze-out indeed displays a clear peak at $\sqrt{s_{NN}}=8.8$ GeV and a possible strong re-enhancement at $\sqrt{s_{NN}}=4.86$ GeV. Our findings thus provide a strong support for the existence of a first-order phase transition at large ${\mu }_B$ and its critical endpoint at a smaller ${\mu }_B$ in the temperature versus baryon chemical potential plane of the QCD phase diagram.

    ↳ nucl-thhep-phnucl-exPLB(2018)·131 citations
35. 35*

    Primordial Black Holes from Inflation and non-Gaussianity

    G. Franciolini🇨🇭 · A. Kehagias🇬🇷 · S. Matarrese🇮🇹 · A. Riotto🇨🇭

    Primordial black holes may owe their origin to the small-scale enhancement of the comoving curvature perturbation generated during inflation. Their mass fraction at formation is markedly sensitive to possible non-Gaussianities in such large, but rare fluctuations. We discuss a path-integral formulation which provides the exact mass fraction of primordial black holes at formation in the presence of non-Gaussianity. Through a couple of classes of models, one based on single-field inflation and the other on spectator fields, we show that restricting to a Gaussian statistics may lead to severe inaccuracies in the estimate of the mass fraction as well as on the clustering properties of the primordial black holes.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2018)·237 citations
36. 36*

    Transient dark energy, cosmological constant boundary crossing and dark energy $w(z)$ data fits

    Dalibor Perkovic🇭🇷 · Hrvoje Stefancic🇭🇷

    The formalism of dark energy based on modeling speed of sound as a function of equation of state parameter is elaborated. A specific model which allows detailed study of cosmological constant boundary crossing is introduced and analytical solutions for the model dynamics are obtained. It is shown how in specific parameter regimes dark energy can be a transient phenomenon. It is further demonstrated how the model reproduces specific features of recent fits of dark energy $w(z)$ to observational data.

    ↳ astro-ph.COgr-qchep-phInt.J.Mod.Phys.D(2018)·9 citations
37. 37*

    Kinetic theory of non-thermal fixed points in a Bose gas

    Isara Chantesana🇩🇪 · Asier Piñeiro Orioli🇩🇪 · Thomas Gasenzer🇩🇪

    We outline a kinetic theory of non-thermal fixed points for the example of a dilute Bose gas, partially reviewing results obtained earlier, thereby extending, complementing, generalizing and straightening them out. We study universal dynamics after a cooling quench, focusing on situations where the time evolution represents a pure rescaling of spatial correlations, with time defining the scale parameter. The non-equilibrium initial condition set by the quench induces a redistribution of particles in momentum space. Depending on conservation laws, this can take the form of a wave-turbulent flux or of a more general self-similar evolution, signaling the critically slowed approach to a non-thermal fixed point. We identify such fixed points using a non-perturbative kinetic theory of collective scattering between highly occupied long-wavelength modes. In contrast, a wave-turbulent flux, possible in the perturbative Boltzmann regime, builds up in a critically accelerated self-similar manner. A key result is the simple analytical universal scaling form of the non-perturbative many-body scattering matrix, for which we lay out the concrete conditions under which it applies. We derive the scaling exponents for the time evolution as well as for the power-law tail of the momentum distribution function, for a general dynamical critical exponent $z$ and an anomalous scaling dimension $\eta$. The approach of the non-thermal fixed point is, in particular, found to involve a rescaling of momenta in time $t$ by $t^{\beta }$, with $\beta =1/z$, within our kinetic approach independent of $\eta$. We confirm our analytical predictions by numerically evaluating the kinetic scattering integral as well as the non-perturbative many-body coupling function. As a side result we obtain a possible finite-size interpretation of wave-turbulent scaling recently measured by Navon et al.

    ↳ cond-mat.quant-gascond-mat.stat-mechhep-phphysics.flu-dynPRA(2019)·77 citations
38. 38*

    Emergent Dark Energy from Dark Matter

    Takeshi Kobayashi🇮🇹 · Pedro G. Ferreira🇬🇧

    We consider the cosmological dynamics of a scalar field in a potential with multiple troughs and peaks. We show that the dynamics of the scalar field will evolve from light dark matter-like behaviour (such as that of a light axion) to a combination of heavy dark matter-like and dark energy-like behaviour. We discuss the phenomenology of such a model, explaining how it can give rise to the cosmological constant, as well as how it can decouple the dark sector densities between the time of recombination and today, for both the homogeneous background and perturbations. The final form of the dark matter is axion-like, but with abundance and primordial isocurvature modes taking very different values from traditional, axionic, dark matter.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2018)·11 citations
39. 39*

    Poincaré-covariant analysis of heavy-quark baryons

    Si-Xue Qin🇨🇳 · Craig D. Roberts🇺🇸 · Sebastian M. Schmidt🇩🇪

    We use a symmetry-preserving truncation of meson and baryon bound-state equations in quantum field theory in order to develop a unified description of systems constituted from light- and heavy-quarks. In particular, we compute the spectrum and leptonic decay constants of ground-state pseudoscalar- and vector-mesons: $q^{\prime }\bar{q}$, $Q^{\prime }\bar{Q}$, with $q^{\prime },q=u,d,s$ and $Q^{\prime },Q=c,b$; and the masses of $J^P=3/2^{+}$ baryons and their first positive-parity excitations, including those containing one or more heavy quarks. This Poincaré-covariant analysis predicts that such baryons have a complicated angular momentum structure. For instance, the ground states are all primarily $S$-wave in character, but each possesses $P$-, $D$- and $F$-wave components, with the $P$-wave fraction being large in the $qqq$ states; and the first positive-parity excitation in each channel has a large $D$-wave component, which grows with increasing current-quark mass, but also exhibits features consistent with a radial excitation. The configuration space extent of all such baryons decreases as the mass of the valence-quark constituents increases.

    ↳ nucl-thhep-phPRD(2018)·60 citations
40. 40*

    Polarized anisotropic spectral distortions of the CMB: Galactic and extragalactic constraints on photon-axion conversion

    Suvodip Mukherjee🇺🇸 · Rishi Khatri🇮🇳 · Benjamin D. Wandelt🇺🇸

    We revisit the cosmological constraints on resonant and non-resonant conversion of photons to axions in the cosmological magnetic fields. We find that the constraints on photon-axion coupling and primordial magnetic fields are much weaker than previously claimed for low mass axion like particles with masses $m_{\mathrm{a}}\lesssim 5\times 10^{-13}\text{eV}$. In particular we find that the axion mass range $10^{-14}\text{eV}\le m_{\mathrm{a}}\le 5\times 10^{-13}\text{eV}$ is not excluded by the CMB data contrary to the previous claims. We also examine the photon-axion conversion in the Galactic magnetic fields. Resonant conversion in the large scale coherent Galactic magnetic field results in $100\%$ polarized anisotropic spectral distortions of the CMB for the mass range $10^{-13}\text{eV}\lesssim m_{\mathrm{a}}\lesssim 10^{-11}\text{eV}$. The polarization pattern traces the transverse to line of sight component of the Galactic magnetic field while both the anisotropy in the Galactic magnetic field and electron distribution imprint a characteristic anisotropy pattern in the spectral distortion. Our results apply to scalar as well as pseudoscalar particles. For conversion to scalar particles, the polarization is rotated by $90^{\circ }$ allowing us to distinguish them from the pseudoscalars. For $m_{\mathrm{a}}\lesssim 10^{-14}\text{eV}$ we have non-resonant conversion in the small scale turbulent magnetic field of the Galaxy resulting in anisotropic but unpolarized spectral distortion in the CMB. These unique signatures are potential discriminants against the isotropic and non-polarized signals such as primary CMB, and $\mu$ and $y$ distortions with the anisotropic nature making it accessible to experiments with only relative calibration like Planck, LiteBIRD, and CORE. We forecast for PIXIE as well as for these experiments using Fisher matrix formalism.

    ↳ astro-ph.COhep-phhep-thJCAP(2018)·54 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.