Tue·May 15, 2018Tuesday·May 15, 2018

1. 01*

   Investigating the exclusive vector meson photoproduction in nuclear collisions at Run 2 LHC energies

   V. P. Goncalves🇧🇷 · M. V. T. Machado🇧🇷 · B. D. Moreira🇧🇷 · F. S. Navarra🇧🇷 · G. Sampaio dos Santos🇧🇷

   We investigate the theoretical uncertainty on the predictions for the photoproduction of $\rho$ and $J/\Psi$ states in nucleus-nucleus collisions at Run 2 LHC energies using the Color Dipole formalism. The results for rapidity distributions and total cross sections are presented. Moreover, we compare directly the theoretical results to the recent preliminary data from ALICE collaboration on $\rho$ production in $PbPb$ collisions at central rapidity.

   hep-phhep-ex0 citations
2. 02*

   Higgs relaxation after inflation

   Nayara Fonseca🇩🇪 · Enrico Morgante🇩🇪 · Geraldine Servant🇩🇪

   We show that the mechanism of cosmological relaxation of the electroweak scale can take place independently of the inflation mechanism, thus relieving burdens from the original relaxion proposal. What eventually stops the (fast-rolling) relaxion field during its cosmological evolution is the production of particles whose mass is controlled by the Higgs vacuum expectation value. We first show that Higgs particle production does not work for that purpose as the Higgs field does not track the minimum of its potential in the regime where Higgs particles get efficiently produced through their coupling to the relaxion. We then focus on gauge boson production. We provide a detailed analysis of the scanning and stopping mechanism and determine the parameter space for which the relaxion mechanism can take place after inflation, while being compatible with cosmological constraints, such as the relaxion dark matter overabundance and Big Bang Nucleosynthesis. We find that the cutoff scale can be as high as two hundreds of TeV. In this approach, the relaxion sector is responsible for reheating the visible sector. The stopping barriers of the periodic potential are large and Higgs-independent, facilitating model-building. The allowed relaxion mass ranges from 200 MeV up to the weak scale. In this scenario, the relaxion field excursion is subplanckian, and is thus many orders of magnitude smaller than in the original relaxion proposal.

   hep-phJHEP(2018)·50 citations
3. 03*

   Intriguing similarities between high-$p_{\mathrm{T}}$ particle production in pp and A-A collisions

   Aditya Nath Mishra🇲🇽 · Antonio Ortiz🇲🇽 · Guy Paic🇲🇽

   In this paper we study the particle production at high transverse momentum ($p_{\mathrm{T}}>8$ GeV/$c$) in both pp and Pb-Pb collisions at LHC energies. The characterization of the spectra is done using a power-law function and the resulting power-law exponent ($n$) is studied as a function of $x_{\mathrm{T}}$ for minimum-bias pp collisions at different $\sqrt{s}$. The functional form of $n$ as a function of $x_{\mathrm{T}}$ exhibits an approximate universal behavior. PYTHIA~8.212 reproduces the scaling properties and therefore, it is used to study the multiplicity-dependent particle production. Going from low to high multiplicities, the power-law exponent decreases. A similar behavior is also observed in heavy-ion collisions when one studies the centrality-dependent particle production. The interpretation of heavy-ion results requires the quantification of the impact of this correlation (multiplicity and high $p_{\mathrm{T}}$) on jet-quenching observables.

   hep-phPRC(2019)·35 citations
4. 04*

   ${\tau }^{-}\to {\nu }_{\tau }{M}_1{M}_2$, with $M_1,M_2$ pseudoscalar or vector mesons

   L. R. Dai🇨🇳 · R. Pavao🇪🇸 · S. Sakai🇪🇸 · E. Oset🇪🇸

   We perform a calculation of the ${\tau }^{-}\to {\nu }_{\tau }{M}_1{M}_2$, with $M_1,M_2$ either pseudoscalar or vector mesons using the basic weak interaction and angular momentum algebra to relate the different processes. The formalism also leads to a different interpretation of the role played by $G$-parity in these decays. We also observe that, while $p$-wave $M_1{M}_2$ production is compatible with chiral perturbation theory and experiment, $VP$ and $VV$ $p$-wave production is clearly incompatible with experiment and we develop the formalism also in this case. We compare our results with experiment and make predictions for unmeasured decays, and we show the value of these reactions, particularly if the $M_1{M}_2$ mass distribution is measured, as a tool to learn about the meson-meson interaction and the nature of some resonances, coupling to two mesons, which are produced in such decays.

   hep-phEPJA(2019)·26 citations
5. 05*

   Effects of strong magnetic fields on quark matter and ${\pi }^0$ properties within nonlocal chiral quark models

   D. Gómez Dumm🇦🇷 · M.F. Izzo Villafañe🇦🇷 · S. Noguera🇪🇸 · V. Pagura🇪🇸 · N.N. Scoccola🇦🇷

   We study the behavior of strongly interacting matter under a strong external magnetic field in the context of chiral quark models that include nonlocal interactions. In particular, we analyze the influence of a constant magnetic field on the chiral quark condensates at zero and finite temperature, studying the deconfinement and chiral restoration critical temperatures and discussing the observed "magnetic catalysis" and "inverse magnetic catalysis" effects. In addition, we analyze in this framework the behavior of the ${\pi }^0$ mass and decay constant. The predictions of nonlocal chiral quark models are compared with results obtained in lattice QCD.

   hep-ph2 citations
6. 06*

   Study of Higgs Effective Couplings at Electron-Proton Colliders

   Hoda Hesari🇮🇷 · Hamzeh Khanpour🇮🇷 · Mojtaba Mohammadi Najafabadi🇮🇷

   We perform a search for beyond the standard model dimension-six operators relevant to the Higgs boson at the Large Hadron Electron Collider (LHeC) and the Future Circular Hadron Electron Collider (FCC-he). With a large amount of data (few ab${}^{-1}$) and collisions at TeV scale, both LHeC and FCC-he provide excellent opportunities to search for the BSM effects. The study is done through the process $e^{-}p\to hj{\nu }_e$ where the Higgs boson decays into a pair of $b\bar{b}$ and we consider the main sources of background processes including a realistic simulation of detector effects. For the FCC-he case, in some signal scenarios to obtain an efficient event reconstruction and to have a good background rejection, jet substructure techniques are employed to reconstruct the boosted Higgs boson in the final state. In order to assess the sensitivity to the dimension-six operators, a shape analysis on the differential cross sections is performed. Stringent bounds are found on the Wilson coefficients of dimension-six operators with the integrated luminosities of 1 ab${}^{-1}$ and 10 ab${}^{-1}$ which in some cases show improvements with respect to the high-luminosity LHC results.

   hep-phPRD(2018)·21 citations
7. 07*

   Resonance $Y(4660)$ as a vector tetraquark and its strong decay channels

   H. Sundu🇹🇷 · S. S. Agaev🇦🇿 · K. Azizi🇹🇷

   The spectroscopic parameters and partial widths of the strong decay channels of the vector meson $Y(4660)$ are calculated by treating it as a bound state of a diquark and antidiquark. The mass and coupling of the $J^{PC}=1^{--}$ tetraquark $Y(4660)$ are evaluated in the context of the two-point sum rule method by taking into account the quark, gluon and mixed condensates up to dimension 10. The widths of the $Y(4660)$ resonance's strong $S$-wave decays to $J/\psi f_0(980)$ and $\psi (2S)f_0(980)$ as well as to $J/\psi f_0(500)$ and $\psi (2S)f_0(500)$ final states are computed. To this end, strong couplings in the relevant vertices are extracted from the QCD sum rule on the light cone supplemented by the technical methods of the soft approximation. The obtained result for the mass of the resonance $m_Y=4677_{-63}^{+71}\mathrm{MeV}$ and the prediction for its total width ${\Gamma }_Y=(64.8\pm 10.8)\mathrm{MeV}$ is in nice agreement with the experimental information.

   hep-phhep-exhep-latPRD(2018)·32 citations
8. 08*

   ${\eta }_{\mathrm{c}}$- and $J/\psi$-isoscalar meson bound states in the hadro-charmonium picture

   J. Ferretti🇨🇳

   We study ${\eta }_{\mathrm{c}}$- and $J/\psi$-isoscalar meson bound states in the hadro-charmonium picture. In the hadro-charmonium, the four $q\bar{q}c\bar{c}$ quarks are arranged in terms of a compact charm-anticharm pair, $c\bar{c}$, embedded in light hadronic matter, $q\bar{q}$, with $q=u$, $d$ or $s$. The interaction between the charmonium core and the light matter can be written in terms of the multipole expansion in QCD, with the leading term being the $E1$ interaction with chromo-electric field ${\mathbf{E}}^a$. The spectrum of ${\eta }_{\mathrm{c}}$- and $J/\psi$-isoscalar meson bound states is calculated and the results compared with the existing experimental data.

   hep-phPLB(2018)·20 citations
9. 09*

   Inverse Seesaw from dynamical $\mathbf{B}-\mathbf{L}$ breaking

   Julia Gehrlein🇪🇸

   The Inverse Seesaw scenario relates the smallness of the neutrino masses to a small $B-L$ breaking parameter. We investigate a possible dynamical generation of the Inverse Seesaw neutrino mass mechanism from the spontaneous breaking of a gauged $U(1{)}_{B-L}$. To obtain an anomaly free theory we need to introduce additional fermions which exhibit an interesting phenomenology. Additionally, we predict a $Z^{\prime }$ boson associated to the broken $B-L$ which preferentially interacts with the dark sector formed by the extra fermions making it particularly elusive.

   hep-ph0 citations
10. 10*

    Pendulum Leptogenesis

    Kazuharu Bamba🇯🇵 · Neil D. Barrie🇯🇵 · Akio Sugamoto🇯🇵 · Tatsu Takeuchi🇺🇸 · Kimiko Yamashita🇯🇵

    We propose a new non-thermal Leptogenesis mechanism that takes place during the reheating epoch, and utilizes the Ratchet mechanism. The interplay between the oscillation of the inflaton during reheating and a scalar lepton leads to a dynamical system that emulates the well-known forced pendulum. This is found to produce driven motion in the phase of the scalar lepton which leads to the generation of a non-zero lepton number density that is later redistributed to baryon number via sphaleron processes. This model successfully reproduces the observed baryon asymmetry, while simultaneously providing an origin for neutrino masses via the seesaw mechanism.

    hep-phPLB(2018)·10 citations
11. 11*

    Hybrid Dark Matter

    Wei Chao🇨🇳

    Dark matter can be produced in the early universe via the freeze-in or freeze-out mechanisms. Both scenarios were investigated in references, but the production of dark matters via the combination of these two mechanisms are not addressed. In this paper we propose a hybrid dark matter model where dark matters have two components with one component produced thermally and the other one produced non-thermally. We present for the first time the analytical calculation for the relic abundance of the Higgs portal hybrid dark matter, then we investigate constraints on the parameter space of the model from dark matter direct and indirect detection experiments.

    hep-ph1 citation
12. 12*

    First global QCD analysis of charged hadron fragmentation functions and their uncertainties at next-to-next-to-leading order

    Maryam Soleymaninia🇮🇷 · Muhammad Goharipour🇮🇷 · Hamzeh Khanpour🇮🇷

    In this paper, we present $SGK18$ FFs, a first global QCD analysis of parton-to-{\it unidentified} charged hadrons fragmentation functions (FFs) at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. This analysis is based on single-inclusive charged hadron production in electron-positron ($e^{-}{e}^{+}$) annihilation. The uncertainties in the extraction of $SGK18$ FFs as well as the corresponding observables are estimated using the "Hessian" technique. We study the quality of the {\tt SGK18} FFs determined in this analysis by comparing with the recent results in literature. We also show how {\tt SGK18} FFs results describe the available data for single-inclusive unidentified charged hadron production in $e^{-}{e}^{+}$ annihilation. We demonstrate that the theoretical uncertainties due to the variation of the renormalization and factorization scales improve when NNLO QCD corrections are considered. We find that the resulting {\tt SGK18} FFs are in good agreement with all data analyzed and the inclusion of NNLO corrections tends to improve the data description with somewhat smaller uncertainty.

    hep-phhep-exPRD(2018)·36 citations
13. 13*

    Baryogenesis via Leptogenesis from Asymmetric Dark Matter and radiatively generated Neutrino mass

    Nimmala Narendra🇮🇳 · Sudhanwa Patra🇮🇳 · Narendra Sahu🇮🇳 · Sujay Shil🇮🇳

    We propose an extension of the standard model (SM) by including a dark sector comprising of three generations of heavy right-handed neutrinos, a singlet scalar and a singlet Dirac fermion, where the latter two particles are stable and are viable candidates of dark matter (DM). In the early Universe, the CP-violating out-of-equilibrium decay of heavy right-handed neutrinos to singlet Dirac fermion and scalar in the dark sector generates a net DM asymmetry. The latter is then transported to the visible sector via a dimension eight operator which conserves $B-L$ symmetry and is in thermal equilibrium above the sphaleron decoupling temperature. An additional light singlet scalar is introduced which mixes with the SM Higgs and pave a path for annihilating the symmetric components of the DM candidates. Then we discuss the constraints on singlet-doublet Higgs mixing from invisible Higgs decay, signal strength at LHC and direct search of DM at terrestrial laboratories. At tree level the neutrinos are shown to be massless since the symmetry of dark sector forbids the interaction of right-handed neutrinos with the SM particles. However, at one loop level the neutrinos acquire sub-eV masses as required by the oscillation experiments.

    hep-phPRD(2018)·19 citations
14. 14*

    Resonant $pp\to W^{+}Zjj$ events at the LHC from a unitarized study of the EChL

    R. L. Delgado🇩🇪 · A. Dobado🇪🇸 · D. Espriu🇪🇸 · C. Garcia-Garcia🇪🇸 · M.J. Herrero🇪🇸 · X. Marcano🇫🇷 · J.J. Sanz-Cillero🇪🇸

    We present a study of the production of vector resonances at the LHC via $W^{+}Z$ vector boson scattering and explore the sensitivities to these resonances for expected LHC luminosities. We work in the framework of the electroweak chiral Lagrangian, where these resonances can be generated dynamically by unitarizing the scattering amplitudes. We implement all these features into a model adapted for MonteCarlo, the IAM-MC, that allows us to give predictions for the sensitivity to these resonances and to the relevant parameters involved for $pp\to W^{+}Zjj$, $pp\to {\ell }_1^{+}{\ell }_1^{-}{\ell }_2^{+}\nu jj$, and $pp\to JJjj$.

    hep-ph1 citation
15. 15*

    Possible existence of a dibaryon candidate $N\Delta$ ($D_{21}$)

    Hongxia Huang🇨🇳 · Xinmei Zhu🇨🇳 · Jialun Ping🇨🇳 · Fan Wang🇨🇳

    Inspired by the experimental report by WASA-at-COSY Collaboration, we investigate the possibile existence of the dibaryon candidate $N\Delta$ with quantum numbers $I{J}^P=21^{+}$ ($D_{21}$). The dynamical calculation shows that we cannot obtain the bound $D_{21}$ state in the models which can obtain the experimental $d^{\ast }$. %although the $D_{21}$ state can bound in the range of parameters in quark models. The low-energy scattering phase shifts of the $N-\Delta$ scattering give the same conclusion. Besides, the mass calculation by using the Gursey-Radicati mass formula and the analysis of the matrix elements of the color magnetic interaction show that the mass of $D_{21}$ is larger than that of $D_{12}$ ($N\Delta$ with $I{J}^P=12^{+}$), which indicate that it is less possible for the $D_{21}$ than the $D_{12}$ to form bound state.

    hep-phnucl-thPRC(2018)·9 citations
16. 16*

    Anomalies in Bottom from new physics in Top

    José Eliel Camargo-Molina🇬🇧 · Alejandro Celis🇩🇪 · Darius A. Faroughy🇸🇮

    We analyze the possibility to accommodate current $b\to s{\ell }^{+}{\ell }^{-}$ anomalies with TeV-scale mediators that couple to right-handed top quarks and muons, contributing to $b\to s{\ell }^{+}{\ell }^{-}$ at the one-loop level. We use the Standard Model Effective Field Theory (SMEFT) framework but also look at specific scenarios by taking into account all possible irreducible representations of the Lorentz and Standard Model gauge group for the mediators. From a global fit of $b\to s{\ell }^{+}{\ell }^{-}$ data and LEP-I observables we find that the Wilson coefficients of two SMEFT operators: ${\mathcal{O}}_{\ell u}=({\bar{\ell }}_{L\mu }{\gamma }^{\alpha }{\ell }_{L\mu })({\bar{t}}_R{\gamma }_{\alpha }{t}_R)$ and ${\mathcal{O}}_{eu}=({\bar{\mu }}_R{\gamma }^{\alpha }{\mu }_R)({\bar{t}}_R{\gamma }_{\alpha }{t}_R)$ need to satisfy ${\mathcal{C}}_{eu}\sim {\mathcal{C}}_{\ell u}$. New physics enters then in $b\to s{\ell }^{+}{\ell }^{-}$ mainly through the operator ${\mathcal{O}}_9=(\bar{s}{\gamma }_{\mu }{P}_{L}b)(\bar{\ell }{\gamma }^{\mu }\ell )$ of the Weak Effective Theory. After discussing all possible mediators, we concentrate on two scenarios: A vector boson in the irreducible representation $Z_{\mu }^{\prime }\sim (1,1,0)$ of the Standard Model gauge group with vectorial coupling to muons, and a combination of two leptoquarks: the scalar $R_2\sim (3,2,7/6)$ and the vector ${\tilde{U}}_{1\mu }\sim (3,1,5/3)$. We derive LHC constraints by recasting di-muon resonance, $pp\to t\bar{t}t\bar{t}$ and SUSY searches. Additionally, we analyze the prospects for discovering these mediators during the high-luminosity phase of the LHC.

    hep-phPLB(2018)·63 citations
17. 17*

    NLO QCD corrections to single vector-like top partner production in association with top quark at the LHC

    Mohamed Sadek Zidi🇩🇿

    The single vector-like top partner hadroproduction in association with top quark in the five and the six-flavour schemes at the LHC is investigated. The inclusive cross section and the differential distributions are evaluated for many benchmark scenarios at leading and next-to-leading orders, both for fixed-order and fixed-order matched to parton shower. The associated Higgs production with a top quark pair, where the final state arises from the decay of the vector-like top partner into a Higgs boson and a top quark, is examined.

    hep-phJHEP(2018)·5 citations
18. 18*

    Chiral Phase Transition with 2+1 quark flavors in an improved soft-wall AdS/QCD Model

    Zhen Fang🇨🇳 · Yue-Liang Wu🇨🇳 · Lin Zhang🇨🇳

    We study the chiral phase transition with 2 + 1 quark flavors in an improved soft-wall AdS/QCD model, which can produce the light meson spectrum and many other low-energy quantities consistent with experiments in the two-flavor case. The chiral transition behaviors of the quark condensates at different quark masses are analysed in detail, and the (m_{u,d}, m_s) phase diagram for the quark sector has been obtained from the improved soft-wall model. We find that the features of the calculated phase diagram are completely consistent with the standard scenario, which is supported by lattice simulations and theoretical arguments. The evidence of a tricritical point on the m_{u,d} = 0 boundary of the (m_{u,d}, m_s) phase diagram is first clearly presented in the bottom-up AdS/QCD.

    hep-phPRD(2018)·27 citations
19. 19*

    Breaking flavor democracy with symmetric perturbations

    Tathagata Ghosh🇺🇸 · Jiajun Liao🇺🇸 · Danny Marfatia🇺🇸 · Tsutomu T. Yanagida🇯🇵

    Flavor democracy broken in the fermion mass matrix by means of small perturbations can give rise to hierarchical fermion masses. We study the breaking of the $S_3^L\times S_3^R$ symmetry associated with democratic mass matrices to a smaller exchange symmetry $S_2^L\times S_2^R$ in the charged lepton, up and down quark sectors. An additional breaking of the $S_2^L\times S_2^R$ symmetry is necessary for the down quark mass matrix, which yields arbitrary perturbations in that sector. On the other hand, we require the neutrino mass matrix to be diagonal at the leading order, with the perturbations left arbitrary due to the absence of any guiding symmetry. We show that the interplay between these two kinds of perturbations reproduces the quark and lepton mass and mixing observables for either hierarchy of neutrino masses.

    hep-phhep-exPLB(2018)·4 citations
20. 20*

    Higgs boson decay $h^0\to m_{V}Z$ in the BLMSSM

    Shu-Min Zhao🇨🇳 · Tai-Fu Feng🇨🇳 · Jian-Bin Chen🇨🇳 · Jing-Jing Feng🇨🇳 · Guo-Zhu Ning🇨🇳 · Hai-Bin Zhang🇨🇳

    In the framework of BLMSSM, the Higgs decays $h^0\to Z\gamma$ and $h^0\to m_{V}Z$ are studied where $m_V$ represents a vector meson($\rho ,\omega ,\varphi ,J/\psi ,{\rm Y}$ etc.). Corrections to the CP-even and CP-odd $h^0\gamma Z$ couplings occur via loop diagrams where new particles are involved. Actually both of them obviously influence the decay rates of $h^0\to Z\gamma$ and $h^0\to m_{V}Z$. Concretely, our obtained numerical result shows that the decay width of $h^0\to Z\gamma$ can be 1.3 times larger than the prediction of the Standard Model(SM). For the light mesons ($\rho ,\omega$), the corrections to $h^0\to m_{V}Z$ are within $15\%\sim 20\%$ still consistent with the SM results. The results of this work would encourage a detection on $h^0\to Z\gamma$ at LHC for exploring new physics beyond SM.

    hep-phPRD(2018)·8 citations
21. 21*

    Four-loop cusp anomalous dimension in QED

    Andrey Grozin🇷🇺

    The 4-loop $C_F^3{T}_F{n}_l$ and 5-loop $C_F^4{T}_F{n}_l$ terms in the HQET field anomalous dimension ${\gamma }_h$ are calculated analytically (the 4-loop one agrees with the recent numerical result [arXiv:1801.08292]). The 4-loop $C_F^3{T}_F{n}_l$ and 5-loop $C_F^4{T}_F{n}_l$ terms in the cusp anomalous dimension $\Gamma (\phi )$ are calculated analytically, exactly in $\phi$ (the $\phi \to \infty$ asymptotics of the 4-loop one agrees with the recent numerical result [arXiv:1707.08315]). Combining these results with the recent 4-loop $d_{FF}{n}_l$ contributions to ${\gamma }_h$ and to the small-$\phi$ expansion of $\Gamma (\phi )$ up to ${\phi }^4$ [arXiv:1708.01221] (recently extended to ${\phi }^6$ [arXiv:1807.05145]) we now have the complete analytical 4-loop result for the Bloch--Nordsieck field anomalous dimension in QED, and the small-$\phi$ expansion of the 4-loop QED cusp anomalous dimension up to ${\phi }^6$.

    hep-phJHEP(2018)·51 citations
22. 22*

    Syndetic Extension of Baryon and Lepton Numbers: Proton Decay and Long-Lived Dark Matter

    Ernest Ma🇺🇸 · Koji Tsumura🇯🇵

    The well-known baryon and lepton numbers of the standard model of quarks and leptons are extended to include new fermions and bosons in a simple structure with several essential features. The usual heavy right-handed neutrino singlets (for neutrino mass and leptogenesis) are related to the axion which solves the strong CP problem. At the same time, baryon number is broken softly, allowing the proton to decay. Associated with this breaking, a long-lived dark-matter candidate (called the pseudo-sakharon) emerges. This new insight connects proton decay to a new component of dark matter.

    hep-phPRD(2018)·4 citations
23. 23*

    Effect of scalar leptoquarks on the lepton flavor violation decays of B meson

    Jin-Huan Sheng🇨🇳 · Ru-Min Wang🇨🇳 · Ya-Dong Yang🇨🇳

    Leptoquarks have been suggested to solve a variety of discrepancies between the expected and observed phenomenon. In this paper, we investigate the effect of scalar leptoquarks on the lepton flavor violating B meson rare decays which involve the quark level transition $\bar{b}\to \bar{s}{\ell }_i^{-}{\ell }_j^{+}(i\ne j)$. The leptoquark parameter space is constrained by using the recently measured upper limits on the $\mathcal{B}(B_s^0\to {\ell }_i^{-}{\ell }_j^{+})$ and $\mathcal{B}(B\to K^{(\ast )}{\ell }_i^{-}{\ell }_j^{+})$. Using such constrained leptoquark parameter space, some relevant physical quantities are also predicted and we find that the constrained New Physics parameters in the leptoquark model have very obvious effects on the relevant physical quantities in this paper. With future measurements of observable in $B\to K^{(\ast )}{\ell }_i^{-}{\ell }_j^{+}$ decays at the LHCb, more and more differentiated from the other NP explanations could be tested.

    hep-phInt.J.Theor.Phys.(2019)·13 citations
24. 24*

    Three-Body $J^P=0^{+},1^{+},2^{+}$ $B^{\ast }{B}^{\ast }\bar{K}$ Bound States

    Manuel Pavon Valderrama🇨🇳

    Three body systems with short-range interactions display universal features that have been extensively explored in atomic physics, but apply to hadron physics as well. Systems composed of two non-interacting identical particles (species H) of mass $M$ and a third particle (species P) of mass $m$ that interacts attractively with the other two have the property that they are more likely to bind for larger values of the mass ratio $M/m$. This is particularly striking if the HHP system is in P-wave (while the interacting pair is in S-wave), in which case one would not normally expect the formation of a three body state. If we assume that the $B^{\ast }\bar{K}$ binds to form the $B_{s1}^{\ast }$ heavy meson and notice that the mass ratio of the $B^{\ast }$ to $\bar{K}$ is $M/m=10.8$, concrete calculations indicate that there should be a three body $B^{\ast }{B}^{\ast }\bar{K}$ bound state between $30-40\mathrm{MeV}$ below the $B_{s1}^{\ast }{B}^{\ast }$ threshold. For the ${\Xi }_{bb}{\Xi }_{bb}\bar{K}$ system the mass imbalance is about $M/m=20.5$ and two bound states are expected to appear, a fundamental and an excited one located at $50-90$ and $5-15\mathrm{MeV}$ below the ${\Xi }_{bb}{\Omega }_{bb\frac{1}{2}}^{\ast }$ threshold (where ${\Omega }_{bb\frac{1}{2}}^{\ast }$ denotes the ${\Xi }_{bb}\bar{K}$ bound state). We indicate the possibility of analogous P-wave three body bound states composed of two heavy baryons and a kaon or antikaon and investigate the conditions under which the Efimov effect could appear in these systems.

    hep-phhep-exnucl-thPRD(2018)·11 citations
25. 25*

    Genuine Extra Yukawas from Extra Higgs, Implications

    George Wei-Shu Hou🇹🇼

    With a second Higgs doublet, extra Yukawa couplings ${\rho }_{ij}$ generally exist. Baryon Asymmetry of the Universe (BAU) can be accounted for by ${\rho }_{tt}\sim \mathcal{O}(1)$, with first order electroweak phase transition (EWPT) arising from $\mathcal{O}(1)$ Higgs quartic couplings. The latter can explain why the observed $h(125)$ boson so resembles the Standard Model (SM) Higgs: with coupling ${\eta }_6\sim \mathcal{O}(1)$ for two-doublet mixing, the $H$--$h$ mixing angle $\cos \gamma \cong -{\eta }_6{v}^2/(m_H^2-m_h^2)$ is suppressed by the $CP$-even boson mass splitting $m_H^2-m_h^2>\mathrm{few}{v}^2$. The approximate alignment, together with the fermion mass-mixing pattern, controls FCNC Higgs effects at low energy. The picture can be probed by $pp\to tt\bar{c}$, $tt\bar{t}$, i.e. same-sign top and triple-top processes at the LHC.

    hep-phhep-ex0 citations
26. 26*

    Implications of the $\rho (s)$ measurements by TOTEM at the LHC

    S.M. Troshin🇷🇺 · N.E. Tyurin🇷🇺

    Implications of the recent measurements of the parameter $\rho (s)$ (ratio of the real to imaginary parts of the forward scattering elastic amplitude) by TOTEM collaboration at $\sqrt{s}=13$ $TeV$ are discussed with emphasis on the rising energy dependence of the ratio of elastic to total cross--sections.

    hep-phMod.Phys.Lett.A(2018)·24 citations
27. 27*

    The impact of the quantized transverse motion on radiation emission in a Dirac harmonic oscillator

    Tobias N. Wistisen🇩🇪 · Antonino Di Piazza🇩🇪

    We investigate the radiation emitted by an ultrarelativistic electron traveling in a 1-dimensional parabolic potential. Having in mind a simplified model for beamstrahlung, we consider the realistic case of the electron motion being highly directional, with the transverse momentum being much smaller than the longitudinal one. In this case we can find solutions of the Dirac equation and we calculate exactly the radiation emission using first-order perturbation theory. We compare the results obtained to that obtained via the semi-classical method of Baier and Katkov which includes quantum effects due to photon recoil in the radiation emission but ignores the quantum nature of the electron motion. On the one hand, we confirm a prediction of the semi-classical method that the emission spectrum should coincide with that in the case of a linearly polarized monochromatic wave. On the other hand, however, we find that the semi-classical method does not yield the exact result when the quantum number describing the transverse motion becomes small. In this way, we address quantitatively the problem of the limits of validity of the semi-classical method, which is known, generally speaking, to be applicable for large quantum numbers. Finally, we also discuss which beam conditions would be necessary to enter the studied regime where also the motion of the particles must be considered quantum mechanically to yield the correct spectrum.

    hep-phPRA(2018)·8 citations
28. 28*

    Hybrid Fluid Models from Mutual Effective Metric Couplings

    Aleksi Kurkela🇨🇭 · Ayan Mukhopadhyay🇦🇹 · Florian Preis🇦🇹 · Anton Rebhan🇦🇹 · Alexander Soloviev🇦🇹

    Motivated by a semi-holographic approach to the dynamics of quark-gluon plasma which combines holographic and perturbative descriptions of a strongly coupled infrared and a more weakly coupled ultraviolet sector, we construct a hybrid two-fluid model where interactions between its two sectors are encoded by their effective metric backgrounds, which are determined mutually by their energy-momentum tensors. We derive the most general consistent ultralocal interactions such that the full system has a total conserved energy-momentum tensor in flat Minkowski space and study its consequences in and near thermal equilibrium by working out its phase structure and its hydrodynamic modes.

    hep-phhep-thnucl-thJHEP(2018)·19 citations
29. 29*

    Thermal correlators in the hadron resonance gas: a dual Hagedorn distance

    E. Megias🇪🇸 · E. Ruiz Arriola🇪🇸 · L.L. Salcedo🇪🇸

    Fluctuations and correlations of conserved quantities in the confined phase of QCD are a viable way to characterize the existence of exotic and missing states with given quantum numbers in the hadronic spectrum. We study a realization of the Hadron Resonance Gas model in the light quark (uds) flavor sector of QCD to study the fluctuations and static correlators of electric charge, baryon number and strangeness. It is also conjectured an interesting duality between the correlators at zero temperature, and the fluctuations of integrated quantities at low temperatures, leading to the appearance of a dual Hagedorn distance for the former.

    hep-phhep-latnucl-thActa Phys.Polon.Supp.(2018)·1 citation
30. 30*

    Directed flow from C-odd gluon correlations at small $x$

    Daniël Boer🇳🇱 · Tom van Daal🇳🇱 · Piet J. Mulders🇳🇱 · Elena Petreska🇳🇱

    It is shown that odd harmonic azimuthal correlations, including the directed flow $v_1$, in forward two-particle production in peripheral proton-nucleus ($pA$) collisions can arise simply from the radial nuclear profile of a large nucleus. This requires consideration of the C-odd part of the gluonic generalized transverse momentum dependent (GTMD) correlator of nucleons in the nucleus. The gluonic GTMD correlator is the Fourier transform of an off-forward hadronic matrix element containing gluonic field strength tensors that are connected by gauge links. It is parametrized in terms of various gluon GTMD distribution functions (GTMDs). We show (in a gauge invariant way) that for the relevant dipole-type gauge link structure in the small-$x$ limit the GTMD correlator reduces to a generalized Wilson loop correlator. The Wilson loop correlator is parametrized in terms of a single function, implying that in the region of small $x$ there is only one independent dipole-type GTMD, which can have a C-odd part. We show that the odderon Wigner distribution, which is related to this C-odd dipole GTMD by a Fourier transform, generates odd harmonics in the two-particle azimuthal correlations in peripheral $pA$ collisions. We calculate the first odd harmonic $v_1$ for forward production within the color glass condensate framework in the limit of a large number of colors. We find that nonzero odd harmonics are present without breaking the rotational symmetry of the nucleus, arising just from its inhomogeneity in the radial direction. Using a CGC model with a cubic action, we illustrate that percent level $v_1$ can arise from this C-odd mechanism. In contrast, we show that only even harmonics arise in diffractive dijet production in ultra-peripheral $pA$ collisions where this gluon dipole GTMD also appears.

    hep-phnucl-thJHEP(2018)·40 citations
31. 31*

    QCD equation of state matched to lattice data and exhibiting a critical point singularity

    Paolo Parotto🇺🇸 · Marcus Bluhm🇵🇱 · Debora Mroczek🇺🇸 · Marlene Nahrgang🇫🇷 · Jacquelyn Noronha-Hostler🇺🇸 · Krishna Rajagopal🇺🇸 · Claudia Ratti🇺🇸 · Thomas Schaefer🇺🇸 · Mikhail Stephanov🇺🇸

    We construct a family of equations of state for QCD in the temperature range 30 MeV $\le T\le$ 800 MeV and in the chemical potential range $0\le {\mu }_B\le$ 450 MeV. These equations of state match available lattice QCD results up to $\mathcal{O}({\mu }_B^4)$ and in each of them we place a critical point in the 3D Ising model universality class. The position of this critical point can be chosen in the range of chemical potentials covered by the second Beam Energy Scan at RHIC. We discuss possible choices for the free parameters, which arise from mapping the Ising model onto QCD. Our results for the pressure, entropy density, baryon density, energy density and speed of sound can be used as inputs in the hydrodynamical simulations of the fireball created in heavy ion collisions. We also show our result for the second cumulant of the baryon number in thermal equilibrium, displaying its divergence at the critical point. In the future, comparisons between RHIC data and the output of the hydrodynamic simulations, including calculations of fluctuation observables, built upon the model equations of state that we have constructed may be used to locate the critical point in the QCD phase diagram, if there is one to be found.

    hep-phnucl-thPRC(2020)·208 citations
32. 32*

    Proceedings of the 2014 Asia-Europe-Pacific School of High-Energy Physics

    Martijn Mulders🇨🇭 · Rohini Godbole (eds.)🇮🇳

    The Asia-Europe-Pacific School of High-Energy Physics is intended to give young physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These proceedings contain lecture notes on quantum field theory and the electroweak Standard Model, the theory of quantum chromodynamics, flavour physics and CP violation, neutrino physics, heavy-ion physics, cosmology and a brief introduction to the principles of instrumentation and detectors for particle physics.

    hep-phhep-ex1 citation
33. 33*

    The relativistic center of mass in field theory with spin

    Cédric Lorcé (Ecole polytechnique, CPHT)🇫🇷

    In order to unravel the origin of the nucleon spin, one has to study in detail the question of orbital angular momentum, and in particular the reference point about which it is defined. With this in mind, we review the concept of relativistic center of mass, generalize the discussion to the case of asymmetric energy-momentum tensors, and establish the link with the light-front formalism. We find that the $p$-wave in the Dirac plane-wave solutions arises from a relativistic quantum-mechanical effect which forces the canonical reference point to depend on the observer. This explains why longitudinal spin is much simpler to study than transverse spin. It is also the reason behind the observation of induced shifts and distortions in the parton distributions defined within the light-front formalism.

    hep-phhep-thEPJC(2018)·48 citations
34. 34*

    Accessing the Gluon Sivers Function at a future Electron-Ion Collider

    L. Zheng🇨🇳 · E.C. Aschenauer🇺🇸 · J.H. Lee🇺🇸 · Bo-Wen Xiao🇨🇳 · Zhong-Bao Yin🇨🇳

    In this work, we present a systematic study on the feasibility of probing the largely unexplored transverse momentum dependent gluon Sivers function (GSF) in open charm production, high p${}_T$ charged di-hadron and di-jet production at a future high energy, high luminosity Electron-Ion Collider (EIC). The Sivers function is a measure for the anisotropy of the parton distributions in momentum space inside a transversely polarized nucleon. It is proposed that it can be studied through single spin asymmetries in the photon-gluon fusion subprocess in electron proton collisions at the EIC. Using a well tuned Monte Carlo model for deep inelastic scattering, we estimate the possible constraints of the GSF from the future EIC data. A comparison of all the accessible measurements illustrates that the di-jet channel is the most promising way to constrain the magnitude of the GSF over a wide kinematic range.

    hep-phhep-exPRD(2018)·53 citations
35. 35*

    Monojet Signatures from Heavy Colored Particles: Future Collider Sensitivities and Theoretical Uncertainties

    Amit Chakraborty🇯🇵 · Silvan Kuttimalai🇺🇸 · Sung Hak Lim🇯🇵 · Mihoko M. Nojiri🇯🇵 · Richard Ruiz🇬🇧

    In models with colored particle $\mathcal{Q}$ that can decay into a dark matter candidate $X$, the relevant collider process $pp\to \mathcal{Q}\bar{\mathcal{Q}}\to X\bar{X}+$jets gives rise to events with significant transverse momentum imbalance. When the masses of $\mathcal{Q}$ and $X$ are very close, the relevant signature becomes monojet-like, and Large Hadron Collider (LHC) search limits become much less constraining. In this paper, we study the current and anticipated experimental sensitivity to such particles at the High-Luminosity LHC at $\sqrt{s}=14\mathrm{TeV}$ with $\mathcal{L}=3{\mathrm{ab}}^{-1}$ of data and the proposed High-Energy LHC at $\sqrt{s}=27\mathrm{TeV}$ with $\mathcal{L}=15{\mathrm{ab}}^{-1}$ of data. We estimate the reach for various Lorentz and QCD color representations of $\mathcal{Q}$. Identifying the nature of $\mathcal{Q}$ is very important to understanding the physics behind the monojet signature. Therefore, we also study the dependence of the observables built from the $pp\to \mathcal{Q}\bar{\mathcal{Q}}+j$ process on $\mathcal{Q}$ itself. Using the state-of-the-art Monte Carlo suites MadGraph5_aMC@NLO+Pythia8 and Sherpa, we find that when these observables are calculated at NLO in QCD with parton shower matching and multijet merging, the residual theoretical uncertainties are comparable to differences observed when varying the quantum numbers of $\mathcal{Q}$ itself. We find, however, that the precision achievable with NNLO calculations, where available, can resolve this dilemma.

    hep-phhep-exEPJC(2018)·6 citations
36. 36*

    Leptonic $CP$ Violation and Proton Decay in SUSY SO(10)

    Rabindra N. Mohapatra🇺🇸 · Matt Severson🇺🇸

    We study the correlation between proton lifetime and leptonic CP violation in a class of renormalizable supersymmetric SO(10) grand unified theories (GUTs) with {\bf 10}, {\bf 126} and {\bf 120} Higgs fields, which provides a unified description of all fermion masses and possibly resolution of the strong CP problem. This specific model is unique in that it can readily be compatible with current proton lifetime limits for a supersymmetry (SUSY) breaking scale as low as 5 TeV due to the presence of a specific Yukawa texture. Our investigation here reveals that proton partial lifetimes predicted by this class of models will be tested by forthcoming proton decay searches; furthermore, a discovery of leptonic CP violation in neutrino oscillations would also lead to substantial reduction of the parameter space of the model.

    hep-phJHEP(2018)·15 citations
37. 37*

    ExDiff Monte Carlo generator for Exclusive Diffraction. Version 2.0. Physics and manual

    R.A. Ryutin🇷🇺

    ExDiff2.0 is a Monte Carlo event generator for simulation of Exclusive Diffractive processes in proton-proton collisions. The present version includes reactions: elastic scattering $pp\to pp$ at 7, 8, 13, 14~TeV; $pp\to p+R+p$, $R=f_0(1500)$, $f_0(1710)$, $f_2(1950)$ at 8 and 13~TeV, $f_2(1270)$ at 8~TeV, $f_2(2220)$ at 13~TeV. In the future versions many processes of Central Exclusive Diffractive Production will be added. This version is linked to PYTHIA 8 (to make resonance decays and hadronization) and also to ROOT and HEPMC output via PYTHIA 8 interface. Also some test files of Born distributions for CEDP of two pions are added.

    hep-ph6 citations
38. 38*

    Gravitational waves from gauge preheating

    Peter Adshead🇺🇸 · John T. Giblin Jr🇺🇸 · Zachary J. Weiner🇺🇸

    We study gravitational wave production during Abelian gauge-field preheating following inflation. We consider both scalar and pseudoscalar inflaton models coupled directly to Abelian gauge fields via either a dilatonic coupling to the gauge-field kinetic term or an axial coupling to a Chern-Simons term. In both cases gravitational waves are produced efficiently during the preheating phase, with a signature louder than most cosmological signals. These gravitational waves can contribute to the radiation energy budget of Universe at a level which will be probed by upcoming cosmic microwave background experiments through $N_{\mathrm{eff}}$. For axially coupled fields the resulting gravitational wave spectrum is helically polarized---a unique feature that can be used to differentiate it from other stochastic gravitational wave backgrounds. We compute the gravitational topological charge and demonstrate that gauge preheating following axion inflation may be responsible for the matter-antimatter asymmetry of the Universe via gravitational leptogenesis.

    ↳ astro-ph.COhep-phPRD(2018)·170 citations
39. 39*

    Electron scattering from a deeply bound nucleon on the light-front

    Frank Vera🇺🇸 · Misak M. Sargsian🇺🇸

    We calculate the cross section of the electron scattering from a bound nucleon within light-front approximation. The advantage of this approximation is the possibility of systematic account for the off-shell effects which become essential in high energy electro-nuclear processes aimed at probing the nuclear structure at small distances. We derive a new dynamical parameter which allows to control the extent of the "off-shellness" of electron - bound-nucleon electromagnetic current for different regions of momentum transfer and initial light-cone momenta of the bound nucleon. The derived cross section is compared with the results of other approaches in treating the off-shell effects in electron-nucleon scattering.

    ↳ nucl-thhep-phnucl-exPRC(2018)·3 citations
40. 40*

    Non-Bessel-Gaussianity and Flow Harmonic Fine-Splitting

    Hadi Mehrabpour🇮🇷 · Seyed Farid Taghavi🇮🇷

    Both collision geometry and event-by-event fluctuations are encoded in the experimentally observed flow harmonic distribution $p(v_n)$ and $2k$-particle cumulants $c_n\{2k\}$. In the present study, we systematically connect these observables to each other by employing Gram-Charlier A series. We quantify the deviation of $p(v_n)$ from Bessel-Gaussianity in terms of flow harmonic fine-splitting. Subsequently, we show that the corrected Bessel-Gaussian distribution can fit the simulated data better than the Bessel-Gaussian distribution in the more peripheral collisions. Inspired by Gram-Charlier A series, we introduce a new set of cumulants $q_n\{2k\}$ that are more natural to study distributions near Bessel-Gaussian. These new cumulants are obtained from $c_n\{2k\}$ where the collision geometry effect is extracted from it. By exploiting $q_2\{2k\}$, we introduce a new set of estimators for averaged ellipticity ${\bar{v}}_2$ which are more accurate compared to $v_2\{2k\}$ for $k>1$. As another application of $q_2\{2k\}$, we show we are able to restrict the phase space of $v_2\{4\}$, $v_2\{6\}$ and $v_2\{8\}$ by demanding the consistency of ${\bar{v}}_2$ and $v_2\{2k\}$ with $q_2\{2k\}$ equation. The allowed phase space is a region such that $v_2\{4\}-v_2\{6\}\gtrsim 0$ and $12v_2\{6\}-11v_2\{8\}-v_2\{4\}\gtrsim 0$, which is compatible with the experimental observations.

    ↳ nucl-thhep-phnucl-exEPJC(2019)·16 citations
41. 41*

    DREENA-B framework: first predictions of $R_{AA}$ and $v_2$ within dynamical energy loss formalism in evolving QCD medium

    Dusan Zigic🇷🇸 · Igor Salom🇷🇸 · Jussi Auvinen🇷🇸 · Marko Djordjevic🇷🇸 · Magdalena Djordjevic🇷🇸

    Dynamical energy loss formalism allows generating state-of-the-art suppression predictions in finite size QCD medium, employing a sophisticated model of high-$p_{\perp }$ parton interactions with QGP. We here report a major step of introducing medium evolution in the formalism though $1+1D$ Bjorken (``B'') expansion, while preserving all complex features of the original dynamical energy loss framework. We use this framework to provide joint $R_{AA}$ and $v_2$ predictions, for the first time within the dynamical energy loss formalism in evolving QCD medium. The predictions are generated for a wide range of observables, i.e. for all types of probes (both light and heavy) and for all centrality regions in both $Pb+Pb$ and $Xe+Xe$ collisions at the LHC. Where experimental data are available, DREENA-B framework leads to a good joint agreement with $v_2$ and $R_{AA}$ data. Such agreement is encouraging, i.e. may lead us closer to resolving $v_2$ puzzle (difficulty of previous models to jointly explain $R_{AA}$ and $v_2$ data), though this still remains to be thoroughly tested by including state-of-the-art medium evolution within DREENA framework. While introducing medium evolution significantly changes $v_2$ predictions, $R_{AA}$ predictions remain robust and moreover in a good agreement with the experimental data; $R_{AA}$ observable is therefore suitable for calibrating parton-medium interaction model, independently from the medium evolution. Finally, for heavy flavor, we observe a strikingly similar signature of the dead-cone effect on both $R_{AA}$ and $v_2$ - we also provide a simple analytical understanding behind this result. Overall, the results presented here indicate that DREENA framework is a reliable tool for QGP tomography.

    ↳ nucl-thhep-phPLB(2019)·72 citations
42. 42*

    Magnetic helicity evolution in a neutron star accounting for the Adler-Bell-Jackiw anomaly

    Maxim Dvornikov (1 and 2)🇷🇺 · Victor B. Semikoz (1) ((1) IZMIRAN, (2) Tomsk State University)🇷🇺

    We analyze the role of the surface terms in the conservation law for the sum of the magnetic helicity density and the chiral imbalance of the charged particle densities. These terms are neglected in the Anomalous MagnetoHydroDynamics (AMHD), where infinite volume is considered typically. We discuss a finite volume system, such as a magnetized neutron star (NS), and study the contribution of the surface terms to the evolution of the magnetic helicity. Accounting for the fast washing out of the chiral imbalance in a nascent NS, we demonstrate that the surface terms contribution can potentially lead to the reconnection of magnetic field lines and subsequent gamma or X-ray bursts observed from magnetars. We derive the additional surface terms originated by the mean spin flux through a volume boundary arising due to macroscopic spin effects in electron-positron plasma. Then, comparing this quantum surface term with the classical one known in standard MHD, we find that the new quantum contribution prevails over classical term for the rigid NS rotation only.

    ↳ astro-ph.HEhep-phJCAP(2018)·11 citations
43. 43*

    The induced surface tension contribution for the equation of state of neutron stars

    Violetta V. Sagun🇺🇦 · Ilidio Lopes🇵🇹 · Aleksei I. Ivanytskyi🇺🇦

    We apply a novel equation of state (EoS) that includes the surface tension contribution induced by interparticle interaction and asymmetry between neutrons and protons, to the study of neutron star (NS) properties. This elaborated EoS is obtained from the virial expansion applied to multicomponent particle mixtures with hard core repulsion. The considered model is in full concordance with all the known properties of normal nuclear matter, provides a high-quality description of the proton flow constraints, hadron multiplicities created during the nuclear-nuclear collision experiments, and equally is consistent with astrophysical data coming from NS observations. The analysis suggests that the best model parameterization gives the incompressibility factor $K_0$, symmetry energy $J$, and symmetry energy slope $L$ at normal nuclear density equal to $200$ MeV, $30$ MeV, and $113.28-114.91$ MeV, respectively. The mass-radius relations found for NSs computed with this EoS are consistent with astrophysical observations.

    ↳ astro-ph.HEhep-phnucl-thApJ(2019)·26 citations
44. 44*

    Nucleon Excited States from Lattice QCD and Hamiltonian Effective Field Theory

    Jia-jun Wu🇦🇺 · Jonathan M. M. Hall🇦🇺 · H. Kamano🇯🇵 · Waseem Kamleh🇦🇺 · T.-S. H. Lee🇺🇸 · Derek B. Leinweber🇦🇺 · Zhan-Wei Liu🇨🇳 · Finn M. Stokes🇦🇺 · Anthony W. Thomas🇦🇺

    An approach for relating the nucleon excited states extracted from lattice QCD and the nucleon resonances of experimental data has been developed using the Hamiltonian effective field theory (HEFT) method. By formulating HEFT in the finite volume of the lattice, the eigenstates of the Hamiltonian model can be related to the energy eigenstates observed in Lattice simulations. By taking the infinite-volume limit of HEFT, information from the lattice is linked to experiment. The approach opens a new window for the study of experimentally-observed resonances from the first principles of lattice QCD calculations. With the Hamiltonian approach, one not only describes the spectra of lattice-QCD eigenstates through the eigenvalues of the finite-volume Hamiltonian matrix, but one also learns the composition of the lattice-QCD eigenstates via the eigenvectors of the Hamiltonian matrix. One learns the composition of the states in terms of the meson-baryon basis states considered in formulating the effective field theory. One also learns the composition of the resonances observed in Nature. In this paper, we will focus on recent breakthroughs in our understanding of the structure of the $N^{\ast }(1535)$, $N^{\ast }(1440)$ and ${\Lambda }^{\ast }(1405)$ resonances using this method.

    ↳ nucl-thhep-lathep-ph2 citations
45. 45*

    Multi-loop techniques for massless Feynman diagram calculations

    A. V. Kotikov🇷🇺 · S. Teber🇫🇷

    We review several multi-loop techniques for analytical massless Feynman diagram calculations in relativistic quantum field theories: integration by parts, the method of uniqueness, functional equations and the Gegenbauer polynomial technique. A brief, historically oriented, overview of some of the results obtained over the decades for the massless 2-loop propagator-type diagram is given. Concrete examples of up to $5$-loop diagram calculations are also provided.

    ↳ hep-thcond-mat.stat-mechhep-phPhys.Part.Nucl.(2019)·68 citations
46. 46*

    Pitfalls of a power-law parameterization of the primordial power spectrum for Primordial Black Hole formation

    Anne M. Green🇬🇧

    Primordial Black Holes (PBHs) can form in the radiation dominated early Universe from the collapse of large density perturbations produced by inflation. A power-law parameterisation of the primordial power spectrum is often used to extrapolate from cosmological scales, where the amplitude of the perturbations is well-measured by Cosmic Microwave Background and Large Scale Structure observations, down to the small scales on which PBHs may form. We show that this typically leads to large errors in the amplitude of the fluctuations on small scales, and hence extremely inaccurate calculations of the abundance of PBHs formed.

    ↳ astro-ph.COhep-phPRD(2018)·13 citations
47. 47*

    Quenches near criticality of the quantum Ising chain---power and limitations of the discrete truncated Wigner approximation

    Stefanie Czischek🇩🇪 · Martin Gärttner🇩🇪 · Markus Oberthaler🇩🇪 · Michael Kastner🇿🇦 · Thomas Gasenzer🇩🇪

    The semi-classical discrete truncated Wigner approximation (dTWA) has recently been proposed as a simulation method for spin-$1/2$ systems. While it appears to provide a powerful approach which shows promising results in higher dimensions and for systems with long-range interactions, its performance is still not well understood in general. Here we perform a systematic benchmark on the one-dimensional transverse-field Ising model and point to limitations of the approximation arising after sudden quenches into the quantum critical regime. Our procedure allows to identify the limitations of the semi-classical simulations and with that to determine the regimes and questions where quantum simulators can provide information which is inaccessible to semi-classics.

    ↳ quant-phcond-mat.quant-gascond-mat.stat-mechhep-phQuantum Sci.Technol.(2018)·19 citations
48. 48*

    A Direct Probe of Mass Density Near Inspiraling Binary Black Holes

    Lisa Randall🇺🇸 · Zhong-Zhi Xianyu🇺🇸

    Now that LIGO has revealed the existence of a large number of binary black holes, identifying their origin becomes an important challenge. They might originate in more isolated regions of the galaxy or alternatively they might reside in dense environments such as galactic centers or globular clusters. In the latter case, their center of mass motion as well as their orbital parameters should lead to observable changes in the waveforms, which would reflect their gravitational interactions with the surrounding matter. This would be reflected in the gravitational wave signal by a net phase change or even a time-dependent Doppler shift. We show that this time-dependence might be observable in future space gravitational wave detectors such as LISA which could provide direct information about the black hole binary environments and otherwise invisible ambient mass.

    ↳ gr-qcastro-ph.HEhep-phhep-thApJ(2019)·69 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.