Wed·Aug 9, 2017Wednesday·August 9, 2017

1. 01*

   Signals of New Gauge Bosons in Gauged Two Higgs Doublet Model

   Wei-Chih Huang🇩🇰 · Hiroyuki Ishida🇹🇼 · Chih-Ting Lu🇹🇼 · Yue-Lin Sming Tsai🇹🇼 · Tzu-Chiang Yuan🇹🇼

   Recently a gauged two Higgs doublet model, in which the two Higgs doublets are embedded into the fundamental representation of an extra local $SU(2{)}_H$ group, is constructed. Both the new gauge bosons $Z^{\prime }$ and $W^{\prime (p,m)}$ are electrically neutral. While $Z^{\prime }$ can be singly produced at colliders, $W^{\prime (p,m)}$, which is heavier, must be pair produced. We explore the constraints of $Z^{\prime }$ using the current Drell-Yan type data from the Large Hadron Collider. Anticipating optimistically that $Z^{\prime }$ can be discovered via the clean Drell-Yan type signals at high luminosity upgrade of the collider, we explore the detectability of extra heavy fermions in the model via the two leptons/jets plus missing transverse energy signals from the exotic decay modes of $Z^{\prime }$. For the $W^{\prime (p,m)}$ pair production in a future 100 TeV proton-proton collider, we demonstrate certain kinematical distributions for the two/four leptons plus missing energy signals have distinguishable features from the Standard Model background. In addition, comparisons of these kinematical distributions between the gauged two Higgs doublet model and the littlest Higgs model with T-parity, the latter of which can give rise to the same signals with competitive if not larger cross sections, are also presented.

   hep-phhep-exEPJC(2018)·17 citations
2. 02*

   Mass modification of hot pions in magnetized dense medium

   Arghya Mukherjee🇮🇳 · Snigdha Ghosh🇮🇳 · Mahatsab Mandal🇮🇳 · Pradip Roy🇮🇳 · Sourav Sarkar🇮🇳

   A phenomenological pion-nucleon interaction is used to obtain pionic mass modification in presence of constant homogeneous magnetic field background at finite temperature and chemical potential in the real time formalism of thermal field theory. The magnetically modified propagator in its complete form is used to obtain the one loop self-energy for pions. For charged pions we find that the effective mass increases with the magnetic field at given temperature and chemical potential. Since the transverse momentum of charged pion is quantized and its contribution to Dyson-Schwinger Equation is large compared to the loop correction, the charged pion mass remains constant with both temperature and chemical potential for a given landau level. In order to unveil the role of the real part of the self-energy, we also calculate the effective mass neglecting the trivial shift. The effective mass for charged pions shows an oscillatory behavior which is attributed to the thermal contribution of the self-energy. It is argued that the magnetic field dependent vacuum contribution to the self-energy influences the behavior of the effective mass both qualitatively and quantitatively. We also find that very large field is necessary for neutral pions to condense.

   hep-phPRD(2017)·18 citations
3. 03*

   Two loop QCD corrections for the process Pseudo-scalar Higgs $\to 3$ partons

   Pulak Banerjee🇮🇳 · Prasanna K. Dhani🇮🇳 · V. Ravindran🇮🇳

   We present virtual contributions up to two loop level in perturbative Quantum Chromodynamic (QCD) to the decay of pseudo-scalar Higgs boson ($A$) to three gluons ($g$) and also to quark ($q$), anti-quark ($\overline{q}$) and a gluon. With appropriate crossing, they are well suited for predicting the differential distribution of $A$ in association with a jet in hadron colliders up to next-to-next-to-leading order (NNLO) in strong coupling constant and also for the subsequent decay of $A$ to hadrons. We use effective field theory approach to integrate out the top quarks in the heavy top limit. The resulting theory involves two pseudo-scalar composite operators describing the interaction of $A$ with gluons as well as with quark and anti-quark. We perform our computation in dimensional regularisation and use minimal subtraction ($\overline{MS}$) scheme to renormalise strong coupling constant as well as the composite operators. The ultraviolet (UV) finite amplitudes contain infrared (IR) divergences that are found to be in agreement with the predictions by Catani. For both the amplitudes namely $A\to ggg$ and $A\to q\overline{q}g$, the leading transcendental terms at one and two loops are found to be identical to those in a three point form factor (FF) of the half-BPS operator in $\mathcal{N}=4$ Supersymmetric Yang Mills (SYM) theory when the QCD color factors are adjusted in a specific way. We present our results in terms of harmonic polylogs well suited for further numerical study.

   hep-phhep-exJHEP(2017)·20 citations
4. 04*

   Particle production at energies available at the CERN Large Hadron Collider within evolutionary model

   Yu. M. Sinyukov🇺🇦 · V. M. Shapoval🇺🇦

   The particle yields and particle number ratios in Pb+Pb collisions at the LHC energy $\sqrt{s_{NN}}=2.76$ TeV are described within the integrated hydrokinetic model (iHKM) at the two different equations of state (EoS) for the quark-gluon matter and the two corresponding hadronization temperatures, $T=165$ MeV and $T=156$ MeV. The role of particle interactions at the final afterburner stage of the collision in the particle production is investigated by means of comparison of the results of full iHKM simulations with those where the annihilation and other inelastic processes (except for resonance decays) are switched off after hadronization/particlization, similarly as in the thermal models. An analysis supports the picture of continuous chemical freeze-out in the sense that the corrections to the sudden chemical freeze-out results, which arise because of the inelastic reactions at the subsequent evolution times, are noticeable and improve the description of particle and number ratios. An important observation is that although the particle number ratios with switched-off inelastic reactions are quite different at different particlization temperatures which are adopted for different equations of state to reproduce experimental data, the complete iHKM calculations bring very close results in both cases.

   hep-phnucl-exnucl-thPRC(2018)·8 citations
5. 05*

   Light-by-light scattering in Double-Logarithmic Approximation

   B.I. Ermolaev🇷🇺 · S.I. Troyan🇷🇺

   In the present paper we consider the elastic 2 -> 2 -scattering of virtual photons at high energies in the forward kinematics at zero and non-zero values of t. Accounting for both gluon and quark double-logarithmic (DL) contributions to all orders in the QCD coupling, we obtain explicit expressions for amplitudes of this process in Double-Logarithmic Approximation (DLA). First we keep the QCD coupling fixed and then account for running coupling effects. Applying the saddle-point method to the obtained expressions for the scattering amplitude, we calculate the high-energy asymptotics of the amplitude, which proved to be of the Regge form. The Reggeon bears the vacuum quantum numbers and therefore it is a new, DL contribution to Pomeron. Comparison of the DL Pomeron to the BFKL Pomeron shows that contribution of the DL Pomeron to the high-energy asymptotics is of the same order as contribution of the BFKL Pomeron, so the DL Pomeron should be taken into account together with the BFKL Pomeron. We estimate the applicability region for the asymptotics of the light-by-light scattering amplitude, where the the DL Pomeron can reliably represent the parent amplitude.

   hep-phhep-exEPJC(2018)·3 citations
6. 06*

   Gluon quasidistribution function at one loop

   Wei Wang🇨🇳 · Shuai Zhao🇨🇳 · Ruilin Zhu🇨🇳

   We study the unpolarized gluon quasidistribution function in the nucleon at one loop level in the large momentum effective theory. For the quark quasidistribution, power law ultraviolet divergences arise in the cut-off scheme and an important observation is that they all are subjected to Wilson lines. However for the gluon quasidistribution function, we first point out that the linear ultraviolet divergences also exist in the real diagram which is not connected to any Wilson line. We then study the one loop corrections to parton distribution functions in both cut-off scheme and dimensional regularization to deal with the ultraviolet divergences. In addition to the ordinary quark and gluon distributions, we also include the quark to gluon and gluon to quark splitting diagrams. The complete one-loop matching factors between the quasi and light cone parton distribution functions are presented in the cut-off scheme. We derive the $P^z$ evolution equation for quasi parton distribution functions, and find that the $P^z$ evolution kernels are identical to the DGLAP evolution kernels.

   hep-phhep-exhep-latnucl-thEPJC(2018)·97 citations
7. 07*

   Non-leptonic two-body weak decays of ${\Lambda }_c(2286)$

   C.Q. Geng🇨🇳 · Y.K. Hsiao🇨🇳 · Yu-Heng Lin🇹🇼 · Liang-Liang Liu🇨🇳

   We study the non-leptonic two-body weak decays of ${\Lambda }_c^{+}(2286)\to {\mathbf{B}}_{n}M$ with ${\mathbf{B}}_n$ ($M$) representing as the baryon (meson) states. Based on the $SU(3)$ flavor symmetry, we can describe most of the data reexamined by the BESIII Collaboration with higher precisions. However, our result of $\mathcal{B}({\Lambda }_c^{+}\to p{\pi }^0)=(5.6\pm 1.5)\times 10^{-4}$ is larger than the current experimental limit of $3\times 10^{-4}$ (90\% C.L.) by BESIII. In addition, we find that $\mathcal{B}({\Lambda }_c^{+}\to {\Sigma }^{+}{K}^0)=(8.0\pm 1.6)\times 10^{-4}$, $\mathcal{B}({\Lambda }_c^{+}\to {\Sigma }^{+}{\eta }^{\prime })=(1.0_{-0.8}^{+1.6})\times 10^{-2}$, and $\mathcal{B}({\Lambda }_c^{+}\to p{\eta }^{\prime })=(12.2_{-8.7}^{+14.3})\times 10^{-4}$, which are accessible to the BESIII experiments.

   hep-phhep-exPLB(2018)·65 citations
8. 08*

   Quark-level analogue of nuclear fusion with doubly-heavy baryons

   Marek Karliner🇮🇱 · Jonathan L. Rosner🇺🇸

   The recent discovery by LHCb of the first doubly-charmed baryon ${\Xi }_{cc}^{++}=ccu$ at $3621.40\pm 0.78$ MeV implies a large binding energy $\sim 130$ MeV between the two $c$ quarks. This strong binding enables a quark-rearrangement exothermic reaction ${\Lambda }_c{\Lambda }_c\to {\Xi }_{cc}^{++}n$ with $Q=12$ MeV, which is a quark-level analogue of deuterium-tritium nuclear fusion reaction $DT\to {}^4\mathrm{He}n$. Due to much larger binding energy between two $b$ quarks $\sim 280$ MeV, the analogous reaction with $b$ quarks, ${\Lambda }_b{\Lambda }_b\to {\Xi }_{bb}N$ is expected to have a dramatically larger $Q$-value, $138\pm 12$ MeV.

   hep-phhep-exNature(2017)·30 citations
9. 09*

   Extracting a Short Distance Top Mass with Light Grooming

   Andre H. Hoang🇦🇹 · Sonny Mantry🇺🇸 · Aditya Pathak🇺🇸 · Iain W. Stewart🇺🇸

   We propose a kinematic method based on a factorization formula for precisely measuring the top quark mass $m_t$ in $pp$ collisions using boosted top jets with light soft drop grooming. By using light grooming, which is an order of magnitude less aggressive than typical grooming, we retain a universal description of the top mass scheme and decay effects, while still effectively removing soft contamination from the top jet. We give field theory results for the hadronization corrections for jets induced by a heavy top quark, showing they are described by a universal hadronic parameter that also appears for groomed light quark jets. An important phenomenological application of our results is that one can obtain $m_t$ in a short distance scheme by fitting the hadron level jet mass distributions, predicted by our factorization formula, to data or by Monte-Carlo calibration. The peaked distributions for $pp$ and $e^{+}{e}^{-}$ collisions are similar, up to sensitivity to underlying event which is significantly reduced by soft drop. Since soft drop implies that the $t$ and $\bar{t}$ jet masses each can be independently measured, the analysis enables the use of lepton+jet samples.

   hep-phhep-exnucl-thPRD(2019)·98 citations
10. 10*

    Supergravity Models with 50-100 TeV Scalars, SUSY Discovery at the LHC and Gravitino Decay Constraints

    Amin Aboubrahim🇺🇸 · Pran Nath🇺🇸

    We investigate the possibility of testing supergravity unified models with scalar masses in the range 50-100 TeV and much lighter gaugino masses at the Large Hadron Collider. The analysis is carried out under the constraints that models produce the Higgs boson mass consistent with experiment and also produce dark matter consistent with WMAP and PLANCK experiments. A set of benchmarks in the supergravity parameter space are investigated using a combination of signal regions which are optimized for the model set. It is found that some of the models with scalar masses in the 50-100 TeV mass range are discoverable with as little as 100 fb${}^{-1}$ of integrated luminosity and should be accessible at the LHC RUN II. The remaining benchmark models are found to be discoverable with less than 1000 fb${}^{-1}$ of integrated luminosity and thus testable in the high luminosity era of the LHC, i.e., at HL-LHC. It is shown that scalar masses in the 50-100 TeV range but gaugino masses much lower in mass produce unification of gauge coupling constants, consistent with experimental data at low scale, with as good an accuracy (and sometimes even better) as models with low ($\mathcal{O}(1)$ TeV) weak scale supersymmetry. Decay of the gravitinos for the supergravity model benchmarks are investigated and it is shown that they decay before the Big Bang Nucleosynthesis (BBN). Further, we investigate the non-thermal production of neutralinos from gravitino decay and it is found that the non-thermal contribution to the dark matter relic density is negligible relative to that from the thermal production of neutralinos for reheat temperature after inflation up to $10^9$ GeV. An analysis of the direct detection of dark matter for SUGRA models with high scalar masses is also discussed.

    hep-phhep-exPRD(2017)·14 citations
11. 11*

    Expanding the Reach of Heavy Neutrino Searches at the LHC

    Florez Andrés · Gurrola Alfredo · Gui Kaiwen · Patiño Carlos · Restrepo Diego

    The observation of neutrino oscillations establishes that neutrinos (${\nu }_{\ell }$) have non-zero mass and provides one of the more compelling arguments for physics beyond the standard model (SM) of particle physics. We present a feasibility study to search for hypothetical Majorana neutrinos ($N_{\ell }$) with TeV scale masses, predicted by extensions of the SM to explain the small but non-zero ${\nu }_{\ell }$ mass, using vector boson fusion (VBF) processes at the 13 TeV LHC. In the context of the minimal Type-I seesaw mechanism (mTISM), the VBF $\ell N_{\ell }$ production cross-section surpasses that of the Drell-Yan process at approximately $m_{N_{\ell }}=1.4$ TeV. We consider $\mu N_{\mu }$ and $\tau N_{\tau }$ production through VBF processes (e.g. $q{q}^{\prime }\to \tau N_{\tau }q{q}^{\prime }$), with subsequent $N_{\mu }$ and $N_{\tau }$ decays to $\mu jj$ and $\tau jj$, as benchmark cases to show the effectiveness of the VBF topology for $N_{\ell }$ seaches at the 13 TeV LHC. The requirement of a dilepton pair combined with four jets, two of which are identified as VBF jets with large separation in pseudorapidity and a TeV scale dijet mass, is effective at reducing the SM background. This criteria may provide expected exclusion bounds, at 95\% confidence level, of $m_{N_{\ell }}<1.7$ ($2.4$) TeV, assuming $100$ (1000) fb${}^{-1}$ of 13 TeV data from the LHC and mixing $|V_{\ell N_{\ell }}{|}^2=1$. The use of the VBF topology to search for $m_{N_{\ell }}$ increases the discovery reach at the LHC, with expected significances greater than 5$\sigma$ (3$\sigma$) for $N_{\ell }$ masses up to 1.7 (2.05) TeV using 1000 fb${}^{-1}$ of 13 TeV data from the LHC.

    hep-phPLB(2018)·27 citations
12. 12*

    Entangled de Sitter from Stringy Axionic Bell pair I: An analysis using Bunch Davies vacuum

    Sayantan Choudhury🇮🇳 · Sudhakar Panda🇮🇳

    In this work, we study the quantum entanglement and compute entanglement entropy in de Sitter space for a bipartite quantum field theory driven by axion originating from $\mathbf{Type}\mathbf{IIB}$ string compactification on a Calabi Yau three fold ($\mathbf{C}{\mathbf{Y}}^3$) and in presence of $NS5$ brane. For this compuation, we consider a spherical surface ${\mathbf{S}}^2$, which divide the spatial slice of de Sitter ($\mathbf{d}{\mathbf{S}}_4$) into exterior and interior sub regions. We also consider the initial choice of vaccum to be Bunch Davies state. First we derive the solution of the wave function of axion in a hyperbolic open chart by constructing a suitable basis for Bunch Davies vacuum state using Bogoliubov transformation. We then, derive the expression for density matrix by tracing over the exterior region. This allows us to compute entanglement entropy and R$\acute{e}$nyi entropy in $3+1$ dimension. Further we quantify the UV finite contribution of entanglement entropy which contain the physics of long range quantum correlations of our expanding universe. Finally, our analysis compliments the necessary condition for the violation of Bell's inequality in primordial cosmology due to the non vanishing entanglement entropy for axionic Bell pair.

    ↳ hep-thastro-ph.COgr-qchep-ph+1EPJC(2018)·42 citations
13. 13*

    A magnetic double integral

    David Broadhurst · Wadim Zudilin

    In a recent study of how the output voltage of a Hall plate is affected by the shape of the plate and the size of its contacts, Udo Ausserlechner has come up with a remarkable double integral that can be viewed as a generalization of the classical elliptic "AGM" integral. Here we discuss transformation properties of the integral, which were experimentally observed by Ausserlechner, as well as its analytical and arithmetic features including connections with modular forms.

    ↳ math.NThep-phmath-phmath.CA+1J.Austral.Math.Soc.(2019)·11 citations
14. 14*

    Tests of Lepton Flavour Universality with $b\to s\ell \ell$ transitions at LHCb

    Guido Andreassi🇨🇭

    Semileptonic $b\to s\ell \ell$ processes constitute a good probe for new physics phenomena: new particles contributing to the loops could affect branching fractions and angular distributions, and have different couplings to different lepton families, thus violating lepton flavour universality. Recent results from the LHCb experiment are reviewed.

    ↳ hep-exhep-ph2 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.