Wed·Mar 29, 2017Wednesday·March 29, 2017

1. 01*

   New Physics in $b\to s{\mu }^{+}{\mu }^{-}$: Distinguishing Models through CP-Violating Effects

   Ashutosh Kumar Alok🇮🇳 · Bhubanjyoti Bhattacharya🇺🇸 · Dinesh Kumar🇮🇳 · Jacky Kumar🇮🇳 · David London🇨🇦 · S. Uma Sankar🇮🇳

   At present, there are several measurements of $B$ decays that exhibit discrepancies with the predictions of the SM, and suggest the presence of new physics (NP) in $b\to s{\mu }^{+}{\mu }^{-}$ transitions. Many NP models have been proposed as explanations. These involve the tree-level exchange of a leptoquark (LQ) or a flavor-changing $Z^{\prime }$ boson. In this paper we examine whether it is possible to distinguish the various models via CP-violating effects in $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$. Using fits to the data, we find the following results. Of all possible LQ models, only three can explain the data, and these are all equivalent as far as $b\to s{\mu }^{+}{\mu }^{-}$ processes are concerned. In this single LQ model, the weak phase of the coupling can be large, leading to some sizeable CP asymmetries in $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$. There is a spectrum of $Z^{\prime }$ models; the key parameter is $g_L^{\mu \mu }$, which describes the strength of the $Z^{\prime }$ coupling to ${\mu }^{+}{\mu }^{-}$. If $g_L^{\mu \mu }$ is small (large), the constraints from $B_s^0$-${\bar{B}}_s^0$ mixing are stringent (weak), leading to a small (large) value of the NP weak phase, and corresponding small (large) CP asymmetries. We therefore find that the measurement of CP-violating asymmetries in $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$ can indeed distinguish among NP $b\to s{\mu }^{+}{\mu }^{-}$ models

   hep-phhep-exPRD(2017)·83 citations
2. 02*

   NLO predictions for Higgs boson pair production with full top quark mass dependence matched to parton showers

   G. Heinrich🇩🇪 · S.P. Jones🇩🇪 · M. Kerner🇩🇪 · G. Luisoni🇨🇭 · E. Vryonidou🇳🇱

   We present the first combination of NLO QCD matrix elements for di-Higgs production, retaining the full top quark mass dependence, with a parton shower. Results are provided within both the POWHEG-BOX and MadGraph5_aMC@NLO Monte Carlo frameworks. We assess in detail the theoretical uncertainties and provide differential results. We find that, as expected, the shower effects are relatively large for observables like the transverse momentum of the Higgs boson pair, which are sensitive to extra radiation. However, these shower effects are still much smaller than the differences between the Born-improved HEFT approximation and the full NLO calculation in the tails of the distributions.

   hep-phJHEP(2017)·199 citations
3. 03*

   Probing subnucleon scale fluctuations in ultraperipheral heavy ion collisions

   Heikki Mäntysaari🇺🇸 · Björn Schenke🇺🇸

   We show that introducing subnucleon scale fluctuations constrained by HERA diffractive $J/\Psi$ production data significantly affects the incoherent diffractive $J/\Psi$ production cross section in ultraperipheral heavy ion collisions. We find that the inclusion of the additional fluctuations increases the ratio of the incoherent to the coherent cross section approximately by a factor of $2$, and modifies the transverse momentum spectra of the produced $J/\Psi$ at momenta larger than the scale that corresponds to the distance scale of the subnucleonic fluctuations. We present predictions for $J/\Psi$ production in ultraperipheral heavy ion collisions at $\sqrt{s_{NN}}=5.02\mathrm{TeV}$ at the LHC and $200\mathrm{GeV}$ at RHIC.

   hep-phnucl-thPLB(2017)·121 citations
4. 04*

   Dynamical alignment of visible and dark sector gauge groups

   Rainer Dick🇨🇦

   We discuss a dark family of lepton-like particles with their own "private" gauge bosons under a local SU'(2)xU'(1) symmetry. The product of dark and visible gauge groups SU'(2)xU'(1)xSU_w(2)xU_Y(1) is broken dynamically to the diagonal (vector-like) subgroup SU(2)xU(1) through the coupling of two scalar fields M_i to the Higgs field and the dark lepton-like particles. After substituting vacuum expectation values for the fields M_i, the Higgs doublet couples in the standard way to the left-handed SU'(2) doublet and right-handed singlets of the dark gauge group, but not to the extra gauge bosons. This defines a new Higgs portal, where the "dark leptons" can contribute to the dark matter and interact with Standard Model matter through Higgs exchange. It also defines a dark matter model with internal interactions. At low energies, the Standard Model Higgs boson aligns the two electroweak-type symmetry groups in the visible and dark sectors and generates the masses in both sectors. We also identify charge assignments in the dark sector which allow for the formation of dark atoms as bound states of dark lepton-like particles. The simplest single-component dark matter version of the model predicts a dark matter mass around 96 GeV, but the corresponding nucleon recoil cross section is ruled out by the xenon based experiments. However, multi-component models or models with a dark SU'(2) doublet mediator instead of the Higgs portal would still be viable.

   hep-phastro-ph.CO0 citations
5. 05*

   On the Gauge Invariance of the Decay Rate of False Vacuum

   Motoi Endo🇯🇵 · Takeo Moroi🇯🇵 · Mihoko M. Nojiri🇯🇵 · Yutaro Shoji🇯🇵

   We study the gauge invariance of the decay rate of the false vacuum for the model in which the scalar field responsible for the false vacuum decay has gauge quantum number. In order to calculate the decay rate, one should integrate out the field fluctuations around the classical path connecting the false and true vacua (i.e., so-called bounce). Concentrating on the case where the gauge symmetry is broken in the false vacuum, we show a systematic way to perform such an integration and present a manifestly gauge-invariant formula of the decay rate of the false vacuum.

   hep-phPLB(2017)·34 citations
6. 06*

   A Pati-Salam SUSY GUT with Yukawa Unification

   Zijie Poh🇺🇸 · Stuart Raby🇺🇸 · Zi-zhi Wang🇨🇳

   Previous studies of a three family Yukawa unified supersymmetric grand unified theory (SUSY GUT) with SO(10) or Pati-Salam (PS) gauge symmetry proposed by Raby and students show that this model is able to fit low energy and inflation observables. However, the fit to low energy observables is not great especially for $\sin 2\beta$, and up and down quark masses. In this paper, we show that by choosing PS as the gauge group and modifying the Yukawa sector, the low energy fit improves significantly while other qualities of the model are maintained. In particular, the lightest SUSY particle is the neutralino with mass of order 300 - 500 GeV, the lightest stop and sbottom have mass of order 3 - 5 TeV and the CP odd Higgs mass is of order 5 - 6 TeV, so we are in the decoupling limit for the light Higgs. In addition, we reinterpret gluino simplified model analyses by the ATLAS and CMS collaborations and find that the most stringent gluino mass bound for our model is $M_{\tilde{g}}\sim 1.9\text{TeV}$. The current best fit point, consistent with this bound, with gluino mass $M_{\tilde{g}}=1.9\text{TeV}$ has ${\chi }^2/\text{dof}\approx 1.12$, compared to the best fit point of the previous model with ${\chi }^2/\text{dof}=1.90$. We find that predictions for the electric dipole moment of the electron, the branching ratio $BR(\mu \to e\gamma )$ and the CP violating angle in the lepton sector, $\sin \delta$, are affected significantly as compared to previous results. In summary, we are unable to rule out this model or place an upper bound on gluino mass accessible by this run of the LHC because the ${\chi }^2/\text{dof}$ of this model is well below $2\sigma$ even for a gluino mass as high as 2.7 TeV. On the bright side, this means that this model is still viable and we might find low energy SUSY particles in the near future.

   hep-phPRD(2017)·7 citations
7. 07*

   Twist-3 fragmentation contribution to polarized hyperon production in unpolarized hadronic collisions

   Yuji Koike (Niigata)🇯🇵 · Andreas Metz (Temple)🇺🇸 · Daniel Pitonyak (Penn State Univ.-Berks)🇺🇸 · Kenta Yabe (Niigata)🇯🇵 · Shinsuke Yoshida (LANL)🇺🇸

   It has been known for a long time that hyperons produced in hadronic collisions are polarized perpendicular to the production plane of the reaction. This effect cannot be described by using twist-2 collinear parton correlators only. Here we compute the contribution of twist-3 fragmentation functions to the production of transversely polarized hyperons in unpolarized proton-proton collisions in the framework of collinear factorization. By taking into account the relations among the relevant twist-3 fragmentation functions which follow from the QCD equation of motion and the Lorentz invariance property of the correlators, we present the leading-order cross section for this term.

   hep-phPRD(2017)·31 citations
8. 08*

   One-loop radiative seesaw dark matter and neutrinoless double beta decay with two zero flavor neutrino mass texture

   Teruyuki Kitabayashi🇯🇵 · Shinya Ohkawa🇯🇵 · Masaki Yasuè🇯🇵

   We discuss the linkage between dark matter mass in the one-loop radiative seesaw model and the effective neutrino mass for the neutrino less double beta decay. This linkage, which has been already numerically suggested, is confirmed to be a reasonable relationship by deriving analytical expressions for two zero flavor neutrino mass texture.

   hep-phInt.J.Mod.Phys.A(2017)·20 citations
9. 09*

   Fixed points and flow analysis on off-equilibrium dynamics in the boson Boltzmann equation

   Kenji Fukushima🇯🇵 · Koichi Murase🇯🇵 · Shi Pu🇯🇵

   We consider fixed points of steady solutions and flow directions using the boson Boltzmann equation that is a one-dimensionally reduced kinetic equation after the angular integration. With an elastic collision integral of the two-to-two scattering process, in the dense (dilute) regime where the distribution function is large (small), the boson Boltzmann equation has approximate fixed points with a power-law spectrum in addition to the thermal distribution function. We argue that the power-law fixed point can be exact in special cases. We elaborate a graphical presentation to display evolving flow directions similarly to the renormalization group flow, which explicitly exhibits how fixed points are connected and parameter space is separated by critical lines. We discuss that such a flow diagram contains useful information on thermalization processes out of equilibrium.

   hep-phAnnals Phys.(2017)·8 citations
10. 10*

    ${\Sigma }_{1/2^{-}}^{\ast }(1380)$ in the ${\Lambda }_c^{+}\to \eta {\pi }^{+}\Lambda$ decay

    Ju-Jun Xie🇨🇳 · Li-Sheng Geng🇨🇳

    A ${\Sigma }^{\ast }$ state with spin-parity $J^P=1/2^{-}$ with mass and width around $1380$ MeV and $120$ MeV, refereed to as the ${\Sigma }_{1/2^{-}}^{\ast }(1380)$, has been predicted in several pentaquark models and inferred from the analysis of CLAS $\gamma p$ data. In the present work, we discuss how one can employ the ${\Lambda }_c^{+}\to \eta {\pi }^{+}\Lambda$ decay to test its existence, as well as to study the ${\Sigma }^{\ast }(1385)$ state with $J^P=3/2^{+}$. Because the final ${\pi }^{+}\Lambda$ system is in a pure isospin $I=1$ combination, the ${\Lambda }_c^{+}\to \eta {\pi }^{+}\Lambda$ decay can be an ideal process to study these ${\Sigma }^{\ast }$ resonances. In particular, we show that the decay angle and energy distributions of the ${\pi }^{+}$ are very different for ${\Sigma }^{\ast }(1385)$ and ${\Sigma }_{1/2^{-}}^{\ast }(1380)$. The proposed decay mechanism as well as the existence of the ${\Sigma }_{1/2^{-}}^{\ast }(1380)$ state can be checked by future BESIII and Belle experiments.

    hep-phPRD(2017)·46 citations
11. 11*

    Properties of the light quarks and antiquarks in the statistical approach

    Claude Bourrely🇫🇷 · Jacques Soffer🇺🇸

    In the quantum statistical parton distributions approach proposed more than one decade ago, one imposes relations between quarks and antiquarks expressions, which lead to very specific properties for the antiquarks. These properties have been verified up to now by recent data and it is a real challenge also for forthcoming experimental results, mainly in the high $x$ region.

    hep-ph1 citation
12. 12*

    Three-loop evolution equation for flavor-nonsinglet operators in off-forward kinematics

    V. M. Braun🇩🇪 · A. N. Manashov🇩🇪 · S. Moch🇩🇪 · M. Strohmaier🇩🇪

    Using the approach based on conformal symmetry we calculate the three-loop (NNLO) contribution to the evolution equation for flavor-nonsinglet leading twist operators in the $\overline{\text{MS}}$ scheme. The explicit expression for the three-loop kernel is derived for the corresponding light-ray operator in coordinate space. The expansion in local operators is performed and explicit results are given for the matrix of the anomalous dimensions for the operators up to seven covariant derivatives. The results are directly applicable to the renormalization of the pion light-cone distribution amplitude and flavor-nonsinglet generalized parton distributions.

    hep-phhep-thJHEP(2017)·82 citations
13. 13*

    Discrete symmetries for electroweak natural type-I seesaw mechanism

    Pratik Chattopadhyay🇮🇳 · Ketan M. Patel🇮🇳

    The naturalness of electroweak scale in the models of type-I seesaw mechanism with $\mathcal{O}(1)$ Yukawa couplings requires TeV scale masses for the fermion singlets. In this case, the tiny neutrino masses have to arise from the cancellations within the seesaw formula which are arranged by fine-tuned correlations between the Yukawa couplings and the masses of fermion singlets. We motivate such correlations through the framework of discrete symmetries. In the case of three Majorana fermion singlets, it is shown that the exact cancellation arranged by the discrete symmetries in seesaw formula necessarily leads to two mass degenerate fermion singlets. The remaining fermion singlet decouples completely from the standard model. We provide two candidate models based on the groups $A_4$ and $\Sigma (81)$ and discuss the generic perturbations to this approach which can lead to the viable neutrino masses.

    hep-phNPB(2017)·35 citations
14. 14*

    Scalar color octets and triplets in the SUSY with R-symmetry

    Wojciech Kotlarski🇩🇪

    In this note we report on the recent progress in the study of the strongly interacting sector of the Minimal R-symmetric Supersymmetric Standard Model (MRSSM). First, we discuss the limits originating from the search of the sgluon pair production in the same-sign lepton final state at the LHC. Next, we present the first available in literature calculation of the NLO SQCD corrections to the same-sign squark pair production in the MRSSM. We discuss the relative size of $k$-factors compared to the MSSM and some technical details that led to this result.

    hep-phJ.Phys.Conf.Ser.(2017)·4 citations
15. 15*

    Modified TBM and role of a hidden ${\mathbb{Z}}_2$

    Rome Samanta🇮🇳 · Mainak Chakraborty🇮🇳

    In a residual ${\mathbb{Z}}_2\times {\mathbb{Z}}_2$ symmetry approach, we investigate minimally perturbed Majorana neutrino mass matrices. Constraint relations among the low energy neutrino parameters are obtained. Baryogenesis is realized through flavored leptogenesis mechanism with quasi-degenerate right handed (RH) heavy neutrinos.

    hep-phSpringer Proc.Phys.(2018)·1 citation
16. 16*

    LHCb anomaly in $\mathbf{B}\to {\mathbf{K}}^{\ast }{\mathbf{\mu }}^{+}{\mathbf{\mu }}^{-}$ optimised observables and potential of ${\mathbf{Z}}^{\prime }$ Model

    Ishtiaq Ahmed🇵🇰 · Abdur Rehman🇵🇰

    Over the last few years LHCb with present energies found some discrepancies in $b\to s{\ell }^{+}{\ell }^{-}$ FCNC transitions including anomalies in the angular observables of $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$, particularly in $P_5^{\prime }$, in low dimuon mass region. Recently, these anomalies are confirmed by Belle, CMS and ATLAS. As the direct evidence of physics beyond-the-SM is absent so far, therefore, these anomalies are being interpreted as indirect hint of new physics. In this context, we study the implication of non universal family of $Z^{\prime }$ model to the angular observables $P_{1,2,3}$, $P_{4,5,6}^{\prime }$ and newly proposed lepton flavor universality violation observables, $Q_{4,5}$, in $B\to K^{\ast }(\to K\pi ){\mu }^{+}{\mu }^{-}$ decay channel in the low dimuon mass region. To see variation in the values of these observables from their standard model values, we have chosen the different scenarios of the $Z^{\prime }$ model. It is found that these angular observables are sensitive to the values of the parameters of $Z^{\prime }$ model. We have also found that with the present parametric space of $Z^{\prime }$ model, the $P_5^{\prime }$-anomaly could be accommodated. However, more statistics on the anomalies in the angular observables are helpful to reveal the status of the considered model and, in general, the nature of new physics.

    hep-phhep-exCPC(2018)·20 citations
17. 17*

    Towards gauge coupling unification in left-right symmetric $\mathrm{SU}(3{)}_{\mathrm{c}}\times \mathrm{SU}(3{)}_{\mathrm{L}}\times \mathrm{SU}(3{)}_{\mathrm{R}}\times \mathrm{U}(1{)}_{\mathrm{X}}$ theories

    Chandan Hati🇮🇳 · Sudhanwa Patra🇮🇳 · Mario Reig🇪🇸 · José W.F. Valle🇪🇸 · C.A. Vaquera-Araujo🇪🇸

    We consider the possibility of gauge coupling unification within the simplest realizations of the $\mathrm{SU}(3{)}_{\mathrm{c}}\times \mathrm{SU}(3{)}_{\mathrm{L}}\times \mathrm{SU}(3{)}_{\mathrm{R}}\times \mathrm{U}(1{)}_{\mathrm{X}}$ gauge theory. We present a first exploration of the renormalization group equations governing the "bottom-up" evolution of the gauge couplings in a generic model with free normalization for the generators. Interestingly, we find that for a $\mathrm{SU}(3{)}_{\mathrm{c}}\times \mathrm{SU}(3{)}_{\mathrm{L}}\times \mathrm{SU}(3{)}_{\mathrm{R}}\times \mathrm{U}(1{)}_{\mathrm{X}}$ symmetry breaking scale $M_X$ as low as a few TeV one can achieve unification in the presence of leptonic octets. We briefly comment on possible grand unified theory frameworks which can embed the $\mathrm{SU}(3{)}_{\mathrm{c}}\times \mathrm{SU}(3{)}_{\mathrm{L}}\times \mathrm{SU}(3{)}_{\mathrm{R}}\times \mathrm{U}(1{)}_{\mathrm{X}}$ model as well as possible implications, such as lepton flavour violating physics at the LHC.

    hep-phPRD(2017)·26 citations
18. 18*

    Higgsino Dark Matter or Not: Role of Disappearing Track Searches at the LHC and Future Colliders

    Hajime Fukuda🇯🇵 · Natsumi Nagata🇯🇵 · Hidetoshi Otono🇯🇵 · Satoshi Shirai🇯🇵

    Higgsino in supersymmetric standard models is known to be a promising candidate for dark matter in the Universe. Its phenomenological property is strongly affected by the gaugino fraction in the Higgsino-like state. If this is sizable, in other words, if gaugino masses are less than $\mathcal{O}(10)$ TeV, we may probe the Higgsino dark matter in future non-accelerator experiments such as dark matter direct searches and measurements of electric dipole moments. On the other hand, if gauginos are much heavier, then it is hard to search for Higgsino in these experiments. In this case, due to a lack of gaugino components, the mass difference between the neutral and charged Higgsinos is uniquely determined by electroweak interactions to be around $350$ MeV, which makes the heavier charged state rather long-lived, with a decay length of about $1$ cm. In this letter, we argue that a charged particle with a flight length of $\mathcal{O}(1)$ cm can be probed in disappearing-track searches if we require only two hits in the pixel detector. Even in this case, we can reduce background events with the help of the displaced-vertex reconstruction technique. We study the prospects of this search strategy at the LHC and future colliders for the Higgsino dark matter scenario. It is found that an almost pure Higgsino is indeed within the reach of the future $33$ TeV collider experiments. We then discuss that the interplay among collider and non-accelerator experiments plays a crucial role in testing the Higgsino dark matter scenarios. Our strategy for disappearing-track searches can also enlarge the discovery potential of pure wino dark matter as well as other electroweak-charged dark matter candidates.

    hep-phhep-exPLB(2018)·103 citations
19. 19*

    pySecDec: a toolbox for the numerical evaluation of multi-scale integrals

    S. Borowka🇨🇭 · G. Heinrich🇩🇪 · S. Jahn🇩🇪 · S.P. Jones🇩🇪 · M. Kerner🇩🇪 · J. Schlenk🇬🇧 · T. Zirke🇩🇪

    We present pySecDec, a new version of the program SecDec, which performs the factorisation of dimensionally regulated poles in parametric integrals, and the subsequent numerical evaluation of the finite coefficients. The algebraic part of the program is now written in the form of python modules, which allow a very flexible usage. The optimization of the C++ code, generated using FORM, is improved, leading to a faster numerical convergence. The new version also creates a library of the integrand functions, such that it can be linked to user-specific codes for the evaluation of matrix elements in a way similar to analytic integral libraries.

    hep-phComput.Phys.Commun.(2018)·388 citations
20. 20*

    Preface to the 19th workshop "What comes beyond the standard models", Bled July 11--19, 2016, and links to the talks in the proceedings

    N. S. Mankoc Borstnik🇸🇮 · H. F. B. Nielsen🇩🇰 · M. Y. Khlopov🇫🇷 · D. Lukman🇸🇮

    The contribution contains the preface to the Proceedings to the 19th Workshop "What Comes Beyond the Standard Models", Bled, July 11 - 19, 2016, published in Bled workshops in physics, Vol.17, No. 2, DMFA-Zaloznistvo, Ljubljana, Dec. 2016, links to (most of) the published contributions and section (by M.Yu. Khlopov) on VIA at Bled 2016.

    hep-phhep-exhep-th7 citations
21. 21*

    Factorization and Resummation for Massive Quark Effects in Exclusive Drell-Yan

    Piotr Pietrulewicz🇩🇪 · Daniel Samitz🇦🇹 · Anne Spiering🇩🇪 · Frank J. Tackmann🇩🇪

    Exclusive differential spectra in color-singlet processes at hadron colliders are benchmark observables that have been studied to high precision in theory and experiment. We present an effective-theory framework utilizing soft-collinear effective theory to incorporate massive (bottom) quark effects into resummed differential distributions, accounting for both heavy-quark initiated primary contributions to the hard scattering process as well as secondary effects from gluons splitting into heavy-quark pairs. To be specific, we focus on the Drell-Yan process and consider the vector-boson transverse momentum, $q_T$, and beam thrust, $\mathcal{T}$, as examples of exclusive observables. The theoretical description depends on the hierarchy between the hard, mass, and the $q_T$ (or $\mathcal{T}$) scales, ranging from the decoupling limit $q_T\ll m$ to the massless limit $m\ll q_T$. The phenomenologically relevant intermediate regime $m\sim q_T$ requires in particular quark-mass dependent beam and soft functions. We calculate all ingredients for the description of primary and secondary mass effects required at NNLL${}^{\prime }$ resummation order (combining NNLL evolution with NNLO boundary conditions) for $q_T$ and $\mathcal{T}$ in all relevant hierarchies. For the $q_T$ distribution the rapidity divergences are different from the massless case and we discuss features of the resulting rapidity evolution. Our results will allow for a detailed investigation of quark-mass effects in the ratio of $W$ and $Z$ boson spectra at small $q_T$, which is important for the precision measurement of the $W$-boson mass at the LHC.

    hep-phJHEP(2017)·48 citations
22. 22*

    The Calculation of Sparticle and Higgs Decays in the Minimal and Next-to-Minimal Supersymmetric Standard Models: SOFTSUSY4.0

    B.C. Allanach🇬🇧 · T. Cridge🇬🇧

    We describe a major extension of the SOFTSUSY spectrum calculator to include the calculation of the decays, branching ratios and lifetimes of sparticles into lighter sparticles, covering the next-to-minimal supersymmetric standard model (NMSSM) as well as the minimal supersymmetric standard model (MSSM). This document acts as a manual for the new version of SOFTSUSY, which includes the calculation of sparticle decays. We present a comprehensive collection of explicit expressions used by the program for the various partial widths of the different decay modes in the appendix.

    hep-phhep-exComput.Phys.Commun.(2017)·33 citations
23. 23*

    Possible $D^{(\ast )}{\bar{D}}^{(\ast )}$ and $B^{(\ast )}{\bar{B}}^{(\ast )}$ molecular states in the extended constituent quark models

    You-Chang Yang🇨🇳 · Zhi-Yun Tan🇨🇳 · Jialun Ping🇨🇳 · Hong-Shi Zong🇨🇳

    The possible neutral $D^{(\ast )}{\bar{D}}^{(\ast )}$ and $B^{(\ast )}{\bar{B}}^{(\ast )}$ molecular states are studied in the framework of the constituent quark models, which is extended by including the $s$-channel one gluon exchange. Using different types of quark-quark potentials, we solve the four-body Schrödinger equation by means of the Gaussian expansion method. The bound states of $D^{(\ast )}{\bar{D}}^{(\ast )}$ with $J^{PC}=1^{++},2^{++}$ and $B^{(\ast )}{\bar{B}}^{(\ast )}$ with $J^{PC}=0^{++},1^{+-},1^{++},2^{++}$ are obtained. The molecular states $D^{\ast }\bar{D}$ with $J^{PC}=1^{++}$ and $B^{\ast }\bar{B}$ with $J^{PC}=1^{+-}$ are good candidates for the $X(3872)$ and $Z_b^0(10610)$, respectively.

    hep-phnucl-thEPJC(2017)·17 citations
24. 24*

    Particle Production in Strong Time-dependent Fields

    D. B. Blaschke🇷🇺 · S. A. Smolyansky🇷🇺 · A. Panferov🇷🇺 · L. Juchnowski🇵🇱

    In these lecture notes we give an introduction to the kinetic equation approach to pair production form the vacuum in strong, time-dependent external fields (dynamical Schwinger process). We first give a derivation of the kinetic equation with the source term for the case of fermions starting from the Dirac equation and for bosons from the Klein-Gordon equation. In a second part we discuss the application of the approach to the situation of external field pulses as single-sheeted functions of time (like the Sauter-pulse) and as multi- sheeted functions approximating the situation in the focal point of counter-propagating laser beams. Special emphasis is on the discussion of the time evolution of the system that exhibits the characteristics of a field-induced phase transition for which we discuss the behaviour of the entropy and particle density of the system. We give an outlook to applications of the approach in describing particle production in strong fields formed in particle and nuclear collisions.

    hep-phphysics.plasm-ph7 citations
25. 25*

    Light baryons below and above the deconfinement transition: medium effects and parity doubling

    Gert Aarts🇬🇧 · Chris Allton🇬🇧 · Davide De Boni🇬🇧 · Simon Hands🇬🇧 · Benjamin Jäger🇬🇧 · Chrisanthi Praki🇬🇧 · Jon-Ivar Skullerud🇮🇪

    We study what happens to the Nucleon, Delta and Omega baryons in the hadronic gas and the quark-gluon plasma, with particular interest in parity doubling and its emergence as the plasma is heated. This is done using simulations of lattice QCD, employing the FASTSUM anisotropic Nf=2+1 ensembles, with four temperatures below and four above the deconfinement transition temperature. Below Tc we find that the positive-parity groundstate masses are largely temperature independent, whereas the negative-parity ones are reduced considerably as the temperature increases. This may be of interest for heavy-ion phenomenology. Close to the transition, the masses are nearly degenerate, in line with the expectation from chiral symmetry restoration. Above Tc we find a clear signal of parity doubling in all three channels, with the effect of the heavier s quark visible.

    ↳ hep-lathep-phnucl-thJHEP(2017)·135 citations
26. 26*

    EoS's of different phases of dense quark matter

    E. J. Ferrer🇺🇸

    Compact stars with significant high densities in their interiors can give rise to quark deconfined phases that can open a window for the study of strongly interacting dense nuclear matter. Recent observations on the mass of two pulsars, PSR J1614-2230 and PSR J0348+0432, have posed a great restriction on their composition, since their equations of state must be hard enough to support masses of about at least two solar masses. The onset of quarks tends to soften the equation of state, but due to their strong interactions, different phases can be realized with new parameters that affect the corresponding equations of state and ultimately the mass-radius relationships. In this paper I will review how the equation of state of dense quark matter is affected by the physical characteristics of the phases that can take place at different baryonic densities with and without the presence of a magnetic field, as well as their connection with the corresponding mass-radius relationship, which can be derived by using different models.

    ↳ nucl-thastro-ph.HEhep-ph3 citations
27. 27*

    Is the Cosmological Constant Problem Properly Posed?

    Philip D. Mannheim🇺🇸

    In applications of Einstein gravity one replaces the quantum-mechanical energy-momentum tensor of sources such as the degenerate electrons in a white dwarf or the black-body photons in the microwave background by c-number matrix elements. And not only that, one ignores the zero-point fluctuations in these sources by only retaining the normal-ordered parts of those matrix elements. There is no apparent justification for this procedure, and we show that it is precisely this procedure that leads to the cosmological constant problem. We suggest that solving the problem requires that gravity be treated just as quantum-mechanically as the sources to which it couples, and show that one can then solve the cosmological constant problem if one replaces Einstein gravity by the fully quantum-mechanically consistent conformal gravity theory.

    ↳ hep-thgr-qchep-phInt.J.Mod.Phys.D(2017)·5 citations
28. 28*

    Luneburg-lens-like structural Pauli attractive core of nuclear force at short distances

    Shigeo Ohkubo🇯🇵

    The nuclear force has been understood to have a repulsive core at short distances, similar to a molecular force, since Jastrow proposed it in 1951. The existence of the repulsion was experimentally confirmed from the proton-proton scattering 1S_0 phase shift, which becomes negative beyond 230 MeV. This repulsion is essential for preventing the nucleon-nucleon system from collapsing by attraction. The origin of the repulsion has been considered to be due to the Pauli principle, similar to the repulsion originally revealed in alpha-alpha scattering, in many studies including recent lattice QCD calculations. On the other hand, very recently it was shown that an inter-nuclear potential including alpha-alpha interactions has a Luneburg-lens-like attraction at short distances rather than repulsion. We show that the nuclear force with an attractive potential at short distances that reproduces the experimental phase shifts well has a Luneburg-lens-like structural Pauli attractive core (SPAC) at short distances and acts as apparent repulsion. The apparent repulsion is caused by the deeply embedded unobservable Pauli forbidden state similar to nucleus-nucleus potentials.

    ↳ nucl-thhep-phnucl-exPRC(2017)·3 citations
29. 29*

    A Glimpse of Gluons through Deeply Virtual Compton Scattering on the Proton

    M. Defurne🇫🇷 · A. Martì Jiménez-Argüello🇫🇷 · Z. Ahmed🇺🇸 · H. Albataineh🇺🇸 · K. Allada🇺🇸 · K. A. Aniol🇺🇸 · V. Bellini🇮🇹 · M. Benali🇫🇷 · W. Boeglin🇺🇸 · P. Bertin🇫🇷 · M. Brossard🇫🇷 · A. Camsonne🇺🇸 and 82 other authors

    The proton is composed of quarks and gluons, bound by the most elusive mechanism of strong interaction called confinement. In this work, the dynamics of quarks and gluons are investigated using deeply virtual Compton scattering (DVCS): produced by a multi-GeV electron, a highly virtual photon scatters off the proton which subsequently radiates a high energy photon. Similarly to holography, measuring not only the magnitude but also the phase of the DVCS amplitude allows to perform 3D images of the internal structure of the proton. The phase is made accessible through the quantum-mechanical interference of DVCS with the Bethe-Heitler (BH) process, in which the final photon is emitted by the electron rather than the proton. We report herein the first full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the high energy regime where the scattering process is expected to occur off a single quark in the proton, these accurate measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction.

    ↳ hep-exhep-phnucl-exNature Commun.(2017)·85 citations
30. 30*

    Critical Temperature in Weakly Interacting Multicomponent Field Theory

    V.I. Yukalov🇷🇺 · E.P. Yukalova🇷🇺

    A method is suggested for calculating the critical temperature in multicomponent field theory with weak interactions. The method is based on self-similar approximation theory allowing for the extrapolation of series in powers of asymptotically small coupling to finite and even infinite couplings. The extrapolation for the critical temperature employs self-similar factor approximants. The found results are in perfect agreement with Monte Carlo simulations.

    ↳ cond-mat.stat-mechhep-phEPJ Web Conf.(2017)·6 citations
31. 31*

    Non-thermal signature of the Unruh effect in field mixing

    Massimo Blasone🇮🇹 · Gaetano Lambiase🇮🇹 · Giuseppe Gaetano Luciano🇮🇹

    Mixing transformations for a uniformly accelerated observer (Rindler observer) are analyzed within the quantum field theory framework as a basis for investigating gravitational effects on flavor oscillations. In particular, the case of two charged boson fields with different masses is discussed. In spite of such a minimal setting, the standard Unruh radiation is found to loose its characteristic thermal interpretation due to the interplay between the Bogolubov transformation hiding in field mixing and the one arising from the Rindler spacetime structure. The modified spectrum detected by the Rindler observer is explicitly calculated in the limit of small mass difference.

    ↳ hep-thgr-qchep-phPRD(2017)·50 citations
32. 32*

    Observational constraints on generalized Proca theories

    Antonio De Felice🇯🇵 · Lavinia Heisenberg🇨🇭 · Shinji Tsujikawa🇯🇵

    In a model of the late-time cosmic acceleration within the framework of generalized Proca theories, there exists a de Sitter attractor preceded by the dark energy equation of state $w_{\mathrm{DE}}=-1-s$, where $s$ is a positive constant. We run the Markov-Chain-Monte-Carlo code to confront the model with the observational data of Cosmic Microwave Background (CMB), baryon acoustic oscillations, supernovae type Ia, and local measurements of the Hubble expansion rate for the background cosmological solutions and obtain the bound $s=0.254_{-0.097}^{+0.118}$ at 95% confidence level (CL). Existence of the additional parameter $s$ to those in the $\Lambda$-Cold-Dark-Matter ($\Lambda$CDM) model allows to reduce tensions of the Hubble constant $H_0$ between the CMB and the low-redshift measurements. Including the cosmic growth data of redshift-space distortions in the galaxy power spectrum and taking into account no-ghost and stability conditions of cosmological perturbations, we find that the bound on $s$ is shifted to $s=0.16_{-0.08}^{+0.08}$ (95 % CL) and hence the model with $s>0$ is still favored over the $\Lambda$CDM model. Apart from the quantities $s,H_0$ and the today's matter density parameter ${\Omega }_{m0}$, the constraints on other model parameters associated with perturbations are less stringent, reflecting the fact that there are different sets of parameters that give rise to a similar cosmic expansion and growth history.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2017)·95 citations
33. 33*

    Paths to equilibrium in non-conformal collisions

    Maximilian Attems🇪🇸 · Jorge Casalderrey-Solana🇬🇧 · David Mateos🇪🇸 · Daniel Santos-Oliván🇪🇸 · Carlos F. Sopuerta🇪🇸 · Miquel Triana🇪🇸 · Miguel Zilhão🇪🇸

    We extend our previous analysis of holographic heavy ion collisions in non-conformal theories. We provide a detailed description of our numerical code. We study collisions at different energies in gauge theories with different degrees of non-conformality. We compare four relaxation times: the hydrodynamization time (when hydrodynamics becomes applicable), the EoSization time (when the average pressure approaches its equilibrium value), the isotropization time (when the longitudinal and transverse pressures approach each other) and the condensate relaxation time (when the expectation value of a scalar operator approaches its equilibrium value). We find that these processes can occur in several different orderings. In particular, the condensate can remain far from equilibrium even long after the plasma has hydrodynamized and EoSized. We also explore the rapidity distribution of the energy density at hydrodynamization. This is far from boost-invariant and its width decreases as the non-conformality increases. Nevertheless, the velocity field at hydrodynamization is almost exactly boost-invariant regardless of the non-conformality. This result may be used to constrain the initialization of hydrodynamic fields in heavy ion collisions.

    ↳ hep-thgr-qchep-phnucl-thJHEP(2017)·71 citations
34. 34*

    Using HAWC to Discover Invisible Pulsars

    Tim Linden🇺🇸 · Katie Auchettl🇺🇸 · Joseph Bramante🇨🇦 · Ilias Cholis🇺🇸 · Ke Fang🇺🇸 · Dan Hooper🇺🇸 · Tanvi Karwal🇺🇸 · Shirley Weishi Li🇺🇸

    Observations by HAWC and Milagro have detected bright and spatially extended TeV gamma-ray sources surrounding the Geminga and Monogem pulsars. We argue that these observations, along with a substantial population of other extended TeV sources coincident with pulsar wind nebulae, constitute a new morphological class of spatially extended TeV halos. We show that HAWCs wide field-of-view unlocks an expansive parameter space of TeV halos not observable by atmospheric Cherenkov telescopes. Under the assumption that Geminga and Monogem are typical middle-aged pulsars, we show that ten-year HAWC observations should eventually observe 37${}_{-13}^{+17}$ middle-aged TeV halos that correspond to pulsars whose radio emission is not beamed towards Earth. Depending on the extrapolation of the TeV halo efficiency to young pulsars, HAWC could detect more than 100 TeV halos from mis-aligned pulsars. These pulsars have historically been difficult to detect with existing multiwavelength observations. TeV halos will constitute a significant fraction of all HAWC sources, allowing follow-up observations to efficiently find pulsar wind nebulae and thermal pulsar emission. The observation and subsequent multi-wavelength follow-up of TeV halos will have significant implications for our understanding of pulsar beam geometries, the evolution of PWN, the diffusion of cosmic-rays near energetic pulsars, and the contribution of pulsars to the cosmic-ray positron excess.

    ↳ astro-ph.HEastro-ph.GAhep-phPRD(2017)·149 citations
35. 35*

    A Nonlocal Approach to the Cosmological Constant Problem

    Sean M. Carroll🇺🇸 · Grant N. Remmen🇺🇸

    We construct a model in which the cosmological constant is canceled from the gravitational equations of motion. Our model relies on two key ingredients: a nonlocal constraint on the action, which forces the spacetime average of the Lagrangian density to vanish, and a dynamical way for this condition to be satisfied classically with arbitrary matter content. We implement the former condition with a spatially-constant Lagrange multiplier associated with the volume form and the latter by including a free four-form gauge field strength in the action. These two features are enough to remove the cosmological constant from the Einstein equation. The model is consistent with all cosmological and experimental bounds on modification of gravity and allows for both cosmic inflation and the present epoch of acceleration.

    ↳ hep-thastro-ph.COhep-phPRD(2017)·28 citations
36. 36*

    The Galactic Contribution to IceCube's Astrophysical Neutrino Flux

    Peter B. Denton🇩🇰 · Danny Marfatia🇺🇸 · Thomas J. Weiler🇺🇸

    High energy neutrinos have been detected by IceCube, but their origin remains a mystery. Determining the sources of this flux is a crucial first step towards multi-messenger studies. In this work we systematically compare two classes of sources with the data: Galactic and extragalactic. We assume that the neutrino sources are distributed according to a class of Galactic models. We build a likelihood function on an event by event basis including energy, event topology, absorption, and direction information. We present the probability that each high energy event with deposited energy $E_{\mathrm{dep}}>60$ TeV in the HESE sample is Galactic, extragalactic, or background. For Galactic models considered the Galactic fraction of the astrophysical flux has a best fit value of $1.3\%$ and is $<9.5\%$ at 90\% CL. A zero Galactic flux is allowed at $<1\sigma$.

    ↳ astro-ph.HEhep-phJCAP(2017)·59 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.