Mon·Oct 22, 2018Monday·October 22, 2018

1. 01*

   Updating Bounds on $R$-Parity Violating Supersymmetry from Meson Oscillation Data

   Florian Domingo🇩🇪 · Herbert K. Dreiner🇩🇪 · Jong Soo Kim🇿🇦 · Manuel E. Krauss🇩🇪 · Victor Martin Lozano🇩🇪 · Zeren Simon Wang🇩🇪

   We update the bounds on $R$-parity violating supersymmetry originating from meson oscillations in the $B_{d/s}^0$ and $K^0$ systems. To this end, we explicitly calculate all corresponding contributions from $R$-parity violating operators at the one-loop level, thereby completing and correcting existing calculations. We apply our results to the derivation of bounds on $R$-parity violating couplings, based on up-to-date experimental measurements. In addition, we consider the possibility of cancellations among flavor-changing contributions of various origins, e.g. from multiple $R$-parity violating couplings or $R$-parity conserving soft terms. Destructive interferences among new-physics contributions could then open phenomenologically allowed regions, for values of the parameters that are naively excluded when the parameters are varied individually.

   hep-phJHEP(2019)·22 citations
2. 02*

   Precision studies of vector-boson production with heavy quarks at the LHC: the case of Z+b jet

   D. Figueroa🇺🇸 · S. Honeywell🇺🇸 · S. Quackenbush🇺🇸 · L. Reina🇺🇸 · C. Reuschle🇺🇸 · D. Wackeroth🇺🇸

   After a brief introduction to the state of the art of theoretical predictions for electroweak vector-boson production with both top and bottom quarks at the LHC, we review the case of Z-boson production with b jets, and discuss the impact of NLO QCD+EW corrections and finite b-quark mass effects on the theoretical prediction for Z+b jet production.

   hep-phPoS(2018)·2 citations
3. 03*

   Precision QCD at the LHC: from the structure of the proton to all-order resummations

   Luca Rottoli🇬🇧

   Experiments at the LHC are collecting a wealth of data with an unprecedented level of precision. As a consequence, the theoretical error is now starting to lag behind the experimental one, and a ceaseless effort is required to reduce the theory uncertainty to match the precision of the data. At hadron colliders, QCD predictions are obtained by convoluting perturbative parton-level results with non-perturbative PDFs, whose precise determination is crucial to reach percent-accurate theoretical predictions. At the parton level, cross sections are obtained through a perturbative expansion in the strong coupling. In some cases, large terms appear at all orders and spoil the convergence of the series. The perturbative description is rescued by resumming the series to all orders, thereby making theory calculations accurate in regions where a fixed-order treatment is not sufficient. In this thesis I first present two global PDF sets where fixed-order calculations are supplemented by threshold and high-energy resummation, respectively. In the first case, it is found that including resummation into PDFs can compensate for the enhancement in the partonic cross sections, with implications for high-mass resonance searches. In the second case, resummation quantitatively improves the description of the HERA structure functions, thus providing evidence of the onset of a new dynamical regime of QCD in the HERA data. I then focus on Higgs production in gluon fusion. The effect of threshold resummation on the total cross section is found to significantly improve the convergence of the perturbative series and to provide a robust method for estimating missing higher order uncertainty. Finally, I present predictions for the Higgs transverse-momentum spectrum both in the inclusive case and within fiducial cuts, exploiting a novel approach where transverse-momentum resummation is performed in direct space.

   hep-phhep-ex4 citations
4. 04*

   PYTHIA and the preoccupied proton

   Thomas A. Trainor🇺🇸

   The PYTHIA Monte Carlo (PMC) has been applied broadly to simulations of high-energy $p$-$p$ and $p$-$\bar{p}$ collisions. The PMC is based on several assumptions, such as that most hadrons result from jet production (multiple parton interactions or MPIs), that $p$-$p$ centrality is relevant and that color reconnection (CR) strongly influences fragmentation to jets. An alternative description is provided by the two-component (soft + hard) model (TCM) of hadron production. TCM analysis of $p$-Pb ensemble-mean-$p_t$ data reveals centrality trends quite different from those estimated via a geometric Glauber model based on the eikonal approximation. Glauber estimates of binary-collision number are three times TCM estimates. Detailed study of $p$-Pb data conflicts with a basic Glauber assumption -- that a projectile proton may interact simultaneously with multiple target nucleons. Instead, in both $p$-$p$ and $p$-A collisions, a $p$-N collision once initiated is exclusive of other possible interactions (during that collision), and within the collision any pair of participant partons may interact -- a $p$-N collision is thus "all or nothing." In this presentation the PMC is challenged by an assortment of contradictory data, and evidence for $p$-N exclusivity is reviewed to make a case for the "preoccupied proton" of the title.

   hep-phEPJ Web Conf.(2019)·0 citations
5. 05*

   DeepXS: Fast approximation of MSSM electroweak cross sections at NLO

   Sydney Otten🇳🇱 · Krzysztof Rolbiecki🇵🇱 · Sascha Caron🇳🇱 · Jong-Soo Kim🇿🇦 · Roberto Ruiz de Austri🇪🇸 · Jamie Tattersall🇩🇪

   We present a deep learning solution to the prediction of particle production cross sections over a complicated, high-dimensional parameter space. We demonstrate the applicability by providing state-of-the-art predictions for the production of charginos and neutralinos at the Large Hadron Collider (LHC) at the next-to-leading order in the phenomenological MSSM-19 and explicitly demonstrate the performance for $pp\to {\tilde{\chi }}_1^{+}{\tilde{\chi }}_1^{-},$ ${\tilde{\chi }}_2^0{\tilde{\chi }}_2^0$ and ${\tilde{\chi }}_2^0{\tilde{\chi }}_1^{\pm }$ as a proof of concept which will be extended to all SUSY electroweak pairs. We obtain errors that are lower than the uncertainty from scale and parton distribution functions with mean absolute percentage errors of well below $0.5\%$ allowing a safe inference at the next-to-leading order with inference times that improve the Monte Carlo integration procedures that have been available so far by a factor of $\mathcal{O}(10^7)$ from $\mathcal{O}(\min )$ to $\mathcal{O}(\mu \mathrm{s})$ per evaluation.

   hep-phhep-exEPJC(2020)·28 citations
6. 06*

   Newly observed $\Omega (2012)$ state and strong decays of the low-lying $\Omega$ excitations

   Zuo-Yun Wang🇨🇳 · Long-Cheng Gui🇨🇳 · Qi-Fang Lü🇨🇳 · Li-Ye Xiao🇨🇳 · Xian-Hui Zhong🇨🇳

   Stimulated by the newly discovered $\Omega (2012)$ resonance at Belle II, in this work we have studied the OZI allowed strong decays of the low-lying $1P$- and $1D$-wave $\Omega$ baryons within the ${}^3{P}_0$ model. It is found that $\Omega (2012)$ is most likely to be a $1P$-wave $\Omega$ state with $J^P=3/2^{-}$. We also find that the $\Omega (2250)$ state could be assigned as a $1D$-wave state with $J^P=5/2^{+}$. The other missing $1P$- and $1D$-wave $\Omega$ baryons may have large potentials to be observed in their main decay channels.

   hep-phPRD(2018)·29 citations
7. 07*

   Exploring Fine-tuning of the Next-to-Minimal Composite Higgs Model

   Daniel Murnane🇦🇺 · Martin J. White🇦🇺 · Anthony G. Williams🇦🇺

   We perform a detailed study of the fine-tuning of the two-site, 4D, Next-to-Minimal Composite Higgs Model (NMCHM), based on the global symmetry breaking pattern $SO(6)\to SO(5)$. Using our previously-defined fine-tuning measure that correctly combines the effect of multiple sources of fine-tuning, we quantify the fine-tuning that is expected to result from future collider measurements of the Standard Model-like Higgs branching ratios, in addition to null searches for the new resonances in the model. We also perform a detailed comparison with the Minimal Composite Higgs Model, finding that there is in general little difference between the fine-tuning expected in the two scenarios, even after measurements at a high-luminosity, 1 TeV linear collider. Finally, we briefly consider the relationship between fine-tuning and the ability of the extra scalar in the NMCHM model to act as a dark matter candidate, finding that the realisation of a $Z_2$ symmetry that stabilises the scalar is amongst the most natural regions in the parameter space, regardless of future collider measurements.

   hep-phJHEP(2019)·7 citations
8. 08*

   Yukawa Unification with Four Higgs Doublets in Supersymmetric GUT

   Bhaskar Dutta🇺🇸 · Yukihiro Mimura🇯🇵

   We discuss the Yukawa coupling unification, a very interesting prediction of the grand unified theory, in the context of scenarios with more than one pair of Higgs doublet since the current LHC constraint has become a problem for the Yukawa unification scenarios with just one pair of Higgs doublet. More than one pair of Higgs doublets can easily arise in missing partner mechanism which solves the doublet-triplet splitting problem. In such a scenario, the Yukawa unification occurs at a medium $\tan \beta$ value, e.g., $\sim$ 30, which corresponds to much smaller threshold corrections compared to usual large $\tan \beta$ scenario for $t-b-\tau$ unification in the context of SO(10) and $b-\tau$ unification in the context of SU(5) models. Further, we show that an additional Higgs doublet pair lowers the sensitivity of the radiative symmetry breaking of the electroweak vacuum.

   hep-phPLB(2019)·16 citations
9. 09*

   Properties of structure functions from helicity components\\ of light quarks and antiquarks in the statistical model

   Claude Bourrely🇫🇷

   In the quantum statistical parton distributions approach proposed more than one decade ago to describe the parton structure, new properties are now understood, in particular, the relation between quarks and antiquarks which leads to very specific properties. The simultaneous treatment of unpolarized and polarized Parton Distribution Functions (PDFs) allows a determination of thermodynamical potentials (the master parameters of the model) which drive their behavior and as a consequence those of the structure functions. The existence of a possible relation between the gluon and a $q\bar{q}$ pair leads to define a toy model for the unpolarized and polarized gluon. In view of forthcoming experimental results in the large $x$ region specific predictions made by the model are presented.

   hep-phPRC(2018)·3 citations
10. 10*

    Asymptotic safety and Conformal Standard Model

    Frederic Grabowski🇵🇱 · Jan H. Kwapisz🇵🇱 · Krzysztof A. Meissner🇵🇱

    We show that the Conformal Standard Model supplemented with asymptotically safe gravity can be valid up to arbitrarily high energies and give a complete description of particle physics phenomena. We restrict the mass of the second scalar particle to $\sim 300$ GeV and the masses of heavy neutrinos to $\sim 340$ GeV. These predictions can be explicitly tested in the nearby future.

    hep-phhep-thPRD(2019)·29 citations
11. 11*

    R-parity Violating Supersymmetric Explanation of the Anomalous Events at ANITA

    Jack H. Collins🇺🇸 · P. S. Bhupal Dev🇺🇸 · Yicong Sui🇺🇸

    The ANITA balloon experiment has observed two EeV-energy, upgoing events originating from well below the horizon. This is puzzling, because (i) no Standard Model (SM) particle is expected to survive passage through Earth at such energies and incident angles, and (ii) no such events were reported by IceCube. In this paper, we address both these issues by invoking a beyond SM interpretation of the EeV events as due to the decay of a long-lived bino in the R-parity violating (RPV) supersymmetry. In particular, a TeV-scale slepton/squark can be resonantly produced through the interaction of the EeV neutrino with electrons/nucleons inside Earth, that decays to a light, long-lived bino, which survives the propagation through Earth matter before decaying back to neutrinos, leptons and/or quarks, thus producing upgoing air showers in the atmosphere near ANITA. We find that the ANITA events can be explained with a GeV-scale bino and $\mathcal{O}(0.1)$ RPV couplings, which are consistent with all existing high and low-energy constraints. We also find that an isotropic neutrino flux is inadequate for a beyond the SM explanation of this kind, and an anisotropic flux must be invoked. Finally, we also address the apparent tension of these observations with IceCube. Various aspects of our interpretation are testable in the near future at different frontiers, such as by the LHC, Belle II, ANITA-IV and IceCube.

    hep-phastro-ph.COastro-ph.HEhep-exPRD(2019)·59 citations
12. 12*

    Sub-leading power corrections to transition form factors of $\eta$ and ${\eta }^{\prime }$ mesons from twist-six contributions

    Janardan P. Singh🇮🇳 · Shesha D. Patel🇮🇳

    Using collinear factorization, we have calculated twist-six corrections to $\eta \gamma$ and ${\eta }^{\prime }\gamma$ transition form factors in QCD. Only a sub-set of light-cone operators of twist-six which can be factorized as a product of two gauge invariant operators has been considered. Resulting power corrections start as $1/Q^4$ but coefficients are smaller compared to their counterparts for twist-four operators. Matrix element of pseudoscalar quark densities for $u$- and $d$-quarks between vacuum and meson state, $h_q$, has considerable influence on the result. Results obtained by superimposing our results on those obtained in literature for leading and sub-leading power corrections for lower twists have been plotted and compared with data.

    hep-phJ.Phys.G(2018)·0 citations
13. 13*

    In-medium properties of the low-lying strange, charm, and bottom baryons in the quark-meson coupling model

    K. Tsushima🇧🇷

    In-medium properties of the low-lying strange, charm, and bottom baryons in symmetric nuclear matter are studied in the quark-meson coupling (QMC) model. Results for the Lorentz-scalar effective masses, mean field potentials felt by the light quarks in the baryons, in-medium bag radii, and the lowest mode bag eigenvalues are presented for those calculated using the updated data. This study completes the in-medium properties of the low-lying baryons in symmetric nuclear matter in the QMC model, for the strange, charm and bottom baryons which contain one or two strange, one charm or one bottom quarks, as well as at least one light quark. Highlight is the prediction of the bottom baryon Lorentz-scalar effective masses, namely, the Lorentz-scalar effective mass of ${\Sigma }_b$ becomes smaller than that of ${\Xi }_b$ at moderate nuclear matter density, $m_{{\Sigma }_b}^{\ast }<m_{{\Xi }_b}^{\ast }$, although in vacuum $m_{{\Sigma }_b}>m_{{\Xi }_b}$. We study further the effects of the repulsive Lorentz-vector potentials on the excitation (total) energies of these bottom baryons.

    hep-phnucl-thPRD(2019)·11 citations
14. 14*

    Chiral symmetry breaking, color superconductivity, and the equation of state for magnetized strange quark matter

    Aman Abhishek🇮🇳 · Hiranmaya Mishra🇮🇳

    We investigate the vacuum structure of dense quark matter in strong magnetic fields at finite temperature and densities in a 3 flavor Nambu Jona Lasinio (NJL) model including the Kobayashi-Maskawa-t'Hooft (KMT) determinant term using a variational method. The method uses an explicit structure for the `ground' state in terms of quark-antiquark condensates as well as diquark condensates. The mass gap equations and the superconducting gap equations are solved self consistently and are used to compute the thermodynamic potential along with the charge neutrality conditions. We also derive the equation of state for the charge neutral strange quark matter in the presence of strong magnetic fields which could be relevant for neutron stars.

    hep-phPRD(2019)·14 citations
15. 15*

    Field theoretic study of electron-electron interaction effects in Dirac liquids

    S. Teber🇫🇷

    The aim of this habilitation thesis is to present recent results, obtained during the period 2012-2017, related to interaction effects in condensed matter physics systems such as planar Dirac liquids, e.g., graphene and graphene-like systems, the surface states of some topological insulators and possibly half-filled fractional quantum Hall systems (for their Dirac composite fermions). These liquids are characterized by gapless bands, strong electron-electron interactions and emergent Lorentz invariance deep in the infra-red. We address a number of important issues raised by experiments on these systems covering subjects of wide current interest in low-energy (condensed matter) as well as high-energy (particle) physics. We shall consider in particular the subtle influence of interactions on transport properties and their supposedly crucial influence on a potential dynamical mass generation. The resolution of these problems will guide us from the thorough examination of the perturbative structure of gauge field theories to the development and application of non-perturbative approaches known from quantum electro/chromo-dynamics to address strong coupling issues.

    ↳ cond-mat.mes-hallhep-phhep-th15 citations
16. 16*

    The Radial Acceleration Relation (RAR): the crucial cases of Dwarf Discs and of Low Surface Brightness galaxies

    Chiara Di Paolo🇮🇹 · Paolo Salucci🇮🇹 · Jean Philippe Fontaine🇮🇹

    McGaugh et al. (2016) have found, in a large sample of disc systems, a tight nonlinear relationship between the total radial accelerations $g$ and their components $g_b$ arisen from the distribution of the baryonic matter [McGaugh_2016]. Here, we investigate the existence of such relation in Dwarf Disc Spirals and Low Surface Brightness galaxies on the basis of [Karukes_2017] and [DiPaolo_2018]. We have accurate mass profiles for 36 Dwarf Disc Spirals and 72 LSB galaxies. These galaxies have accelerations that cover the McGaugh range but also reach out to one order of magnitude below the smallest accelerations present in McGaugh et al. (2016) and span different Hubble Types. We found, in our samples, that the $g$ vs $g_b$ relation has a very different profile and also other intrinsic novel properties, among those, the dependence on a second variable: the galactic radius, normalised to the optical radius $R_{opt}$, at which the two accelerations are measured. We show that the new far than trivial $g$ vs $(g_b,r/R_{opt})$ relationship is nothing else than a direct consequence of the complex, but coordinated mass distributions of the baryons and the dark matter (DM) in disc systems. Our analysis shows that the McGaugh et al. (2016) relation is a limiting case of a new universal relation that can be very well framed in the standard "DM halo in the Newtonian Gravity" paradigm.

    ↳ astro-ph.GAhep-phApJ(2019)·40 citations
17. 17*

    Strong Constraints on Fuzzy Dark Matter from Ultrafaint Dwarf Galaxy Eridanus II

    David J. E. Marsh🇩🇪 · Jens C. Niemeyer🇩🇪

    The fuzzy dark matter (FDM) model treats DM as a bosonic field with astrophysically large de Broglie wavelength. A striking feature of this model is $\mathcal{O}(1)$ fluctuations in the dark matter density on time scales which are shorter than the gravitational timescale. Including for the first time the effect of core oscillations, we demonstrate how such fluctuations lead to heating of star clusters, and thus an increase in their size over time. From the survival of the old star cluster in Eridanus II we infer $m_a\gtrsim 0.6\to 1\times 10^{-19}\text{ eV}$ within modelling uncertainty if FDM is to compose all of the DM, and derive constraints on the FDM fraction at lower masses. The subhalo mass function in the Milky Way implies $m_a\gtrsim 0.8\times 10^{-21}\text{ eV}$ to successfully form Eridanus II. The window between $10^{-21}\text{ eV}\lesssim m_a\lesssim 10^{-20}\text{ eV}$ is affected by narrow band resonances, and the limited applicability of the diffusion approximation. Some of this window may be consistent with observations of Eridanus II and more detailed investigations are required.

    ↳ astro-ph.COastro-ph.GAhep-phPRL(2019)·259 citations
18. 18*

    Formation Redshift of the Massive Black Holes Detected by LIGO

    Razieh Emami🇺🇸 · Abraham Loeb🇺🇸

    We compare the event rate density detected by LIGO to the comoving number density of isolated stellar progenitors and find a range for their formation redshift. Our limit depends on the threshold mass for making the black holes (BHs) but only weakly on the metallicity of their progenitor. If $10\%$ of all BHs are in coalescing binaries, then enough progenitors have formed by $2<z_f<9$.

    ↳ astro-ph.HEastro-ph.SRhep-phhep-th3 citations
19. 19*

    Two body relativistic wave equations

    Riccardo Giachetti🇮🇹 · Emanuele Sorace🇮🇹

    The relativistic quantum mechanics of two interacting particles is considered. We first present a covariant formulation of kinematics and of reduced phase space, giving a short outline of the classical results. We then quantize the systems for the scalar-scalar, fermion-scalar and fermion-fermion cases. We study the spectrum and the spherical waves solutions of the free case. The interaction with central scalar and vector potentials is introduced and the explicit equations are deduced. The one particle and the non relativistic limits are recovered and the general lines for the solution of the boundary value problems are given. We make a numerical analysis of the first two cases with Coulomb interaction. For the two fermions we largely revisit the model we had previously derived in order to uniformize the description for all the three cases. In order to give a complete review we report in Appendix some of the most interesting results obtained for atomic and mesonic systems with Coulomb and Cornell potential interactions respectively.

    ↳ quant-phhep-phhep-thAnnals Phys.(2019)·10 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.