Wed·Jan 3, 2018Wednesday·January 3, 2018

1. 01*

   Muon g-2 and Dark Matter suggest Non-Universal Gaugino Masses: $\mathbf{SU}(5)\times {\mathbf{A}}_4$ case study at the LHC

   Alexander S. Belyaev🇬🇧 · Steve F. King🇬🇧 · Patrick B. Schaefers🇬🇧

   We argue that in order to account for the muon anomalous magnetic moment $g-2$, dark matter and LHC data, non-universal gaugino masses $M_i$ at the high scale are required in the framework of the Minimal Supersymmetric Standard Model (MSSM). We also need a right-handed smuon ${\tilde{\mu }}_R$ with a mass around 100 GeV, evading LHC searches due to the proximity of a neutralino ${\tilde{\chi }}_1^0$ several GeV lighter which allows successful dark matter. We discuss such a scenario in the framework of an $SU(5)$ Grand Unified Theory (GUT) combined with $A_4$ family symmetry, where the three $\overline{5}$ representations form a single triplet of $A_4$ with a unified soft mass $m_F$, while the three $10$ representations are singlets of $A_4$ with independent soft masses $m_{T1},m_{T2},m_{T3}$. Although $m_{T2}$ (and hence ${\tilde{\mu }}_R$) may be light, the muon $g-2$ and relic density also requires light $M_1\simeq 250$ GeV, which is incompatible with universal gaugino masses due to LHC constraints on $M_2$ and $M_3$ arising from gaugino searches. After showing that universal gaugino masses $M_{1/2}$ at the GUT scale are excluded by gluino searches, we provide a series of benchmarks which show that while $M_1=M_2\ll M_3$ is also excluded by chargino searches, $M_1<M_2\ll M_3$ is currently allowed. Even this scenario is almost excluded by the tension between the muon $g-2$, relic density, Dark Matter direct detection and LHC data. The surviving parameter space is characterised by a higgsino mass $\mu \approx -300$ GeV, as required by the muon $g-2$. The LHC will be able to fully test this scenario with the upgraded luminosity via muon-dominated tri- and di-lepton signatures resulting from higgsino dominated ${\tilde{\chi }}_1^{\pm }{\tilde{\chi }}_2^0$ and ${\tilde{\chi }}_1^{+}{\tilde{\chi }}_1^{-}$ production.

   hep-phPRD(2018)·35 citations
2. 02*

   Conditions for the custodial symmetry in multi-Higgs-doublet models

   M. Aa. Solberg🇳🇴

   We derive basis-independent, necessary and sufficient conditions for the custodial symmetry in N-Higgs-doublet models (NHDM) for N > 2, and apply them on some 3HDM examples.

   hep-phhep-thmath-phmath.MPJHEP(2018)·10 citations
3. 03*

   Tomography and gravitational radii for hadrons by three-dimensional structure functions

   S. Kumano🇯🇵 · Qin-Tao Song🇯🇵 · O. V. Teryaev🇷🇺

   Three-dimensional tomography of hadrons can be investigated by generalized parton distributions (GPDs), transverse-momentum-dependent parton distributions (TMDs), and generalized distribution amplitudes (GDAs). The GDA studies had been only theoretical for a long time because there was no experimental measurement until recently, whereas the GPDs and TMDs have been investigated extensively by deeply virtual Compton scattering and semi-inclusive deep inelastic scattering. Here, we report our studies to determine pion GDAs from recent KEKB measurements on the differential cross section of ${\gamma }^{\ast }\gamma \to {\pi }^0{\pi }^0$. Since an exotic-hadron pair can be produced in the final state, the GDAs can be used also for probing internal structure of exotic hadron candidates in future. The other important feature of the GDAs is that the GDAs contain information on form factors of the energy-momentum tensor for quarks and gluons, so that gravitational form factors and radii can be calculated from the determined GDAs. We show the mass (energy) and the mechanical (pressure, shear force) form factors and radii for the pion. Our analysis should be the first attempt for obtaining gravitational form factors and radii of hadrons by analysis of actual experimental measurements. We believe that a new field of gravitational physics is created from the microscopic level in terms of elementary quarks and gluons.

   hep-phhep-exhep-thnucl-thEPJ Web Conf.(2018)·3 citations
4. 04*

   ${\bar{B}}^0$, ${\bar{B}}_s^0$ and $B^{-}$ decays into ${\eta }_c$ plus a scalar meson

   Ju-Jun Xie🇨🇳 · Gang Li🇨🇳

   We investigate the decays of ${\bar{B}}_s^0$, ${\bar{B}}^0$ and $B^{-}$ into ${\eta }_c$ plus a scalar meson in a theoretical framework by taking into account the dominant process for the weak decay of $\bar{B}$ meson into ${\eta }_c$ and a $q\bar{q}$ pair. After hadronization of this $q\bar{q}$ component into pairs of pseudoscalar mesons we obtain certain weights for the pseudoscalar meson-pseudoscalar meson components. The calculation is based on the postulation that the scalar mesons $f_0(500)$, $f_0(980)$ and $a_0(980)$ are dynamically generated states from the pseudoscalar meson-pseudoscalar meson interactions in $S$-wave. Up to a global normalization factor, the $\pi \pi$, $K\bar{K}$ and $\pi \eta$ invariant mass distributions for the decays of ${\bar{B}}_s^0\to {\eta }_c{\pi }^{+}{\pi }^{-}$, ${\bar{B}}_s^0\to {\eta }_c{K}^{+}{K}^{-}$, ${\bar{B}}^0\to {\eta }_c{\pi }^{+}{\pi }^{-}$, ${\bar{B}}^0\to {\eta }_c{K}^{+}{K}^{-}$, ${\bar{B}}^0\to {\eta }_c{\pi }^0\eta$, $B^{-}\to {\eta }_c{K}^0{K}^{-}$ and $B^{-}\to {\eta }_c{\pi }^{-}\eta$ are predicted. Comparison is made with the limited experimental information available and other theoretical calcualtions. Further comparison of these results with coming LHCb measurements will be very valuable to make progress in our understanding of the nature of the low lying scalar mesons, $f_0(500),f_0(980)$ and $a_0(980)$.

   hep-phhep-exEPJC(2018)·14 citations
5. 05*

   A generalized one-loop neutrino mass model with charged particles

   Kingman Cheung🇹🇼 · Hiroshi Okada🇹🇼

   We propose a radiative neutrino-mass model by introducing 3 generations of fermion pairs $E^{-(N+1)/2}{E}^{+(N+1)/2}$ and a couple of multi-charged bosonic doublet fields ${\Phi }_{N/2},{\Phi }_{N/2+1}$, where $N=1,3,5,7,9$. We show that the models can satisfy the neutrino masses and oscillation data, and are consistent with lepton-flavor violations, the muon anomalous magnetic moment, the oblique parameters, and the beta function of the $U(1{)}_Y$ hypercharge gauge coupling. We also discuss the collider signals for various $N$, namely, multi-charged leptons in the final state from the Drell-Yan production of $E^{-(N+1)/2}{E}^{+(N+1)/2}$. In general, the larger the $N$ the more charged leptons will appear in the final state.

   hep-phPRD(2018)·5 citations
6. 06*

   QCD Parameters Correlations from Heavy Quarkonia

   Stephan Narison (LUPM-CNRS Montpellier-FR)🇫🇷

   Correlations between the QCD coupling \alpha_s, the gluon condensate < \alpha_s G^2 >, and the c,b-quark running masses m_c,b in the MS-scheme are explicitly studied (for the first time) from the (axial-)vector and (pseudo)scalar charmonium and bottomium ratios of Laplace sum rules (LSR) evaluated at the \mu-subtraction stability point where PT @N2LO, N3LO and < \alpha_s G^2> @NLO corrections are included. Our results clarify the (apparent) discrepancies between different estimates of < \alpha_s G^2> from J/\psi sum rule but also shows the sensitivity of the sum rules on the choice of the \mu-subtraction scale which does not permit a high-precision estimate of m_c,b. We obtain from the (axial-)vector [resp. (pseudo)scalar] channels <\alpha_s G^2>=(8.5+- 3.0)> [resp. (6.34+-.39)] 10^-2 GeV^4, m_c(m_c)= 1256(30) [resp. 1266(16)] MeV and m_b(m_b)=4192(15) MeV. Combined with our recent determinations from vector channel, one obtains the average: m_c(m_c)= 1263(14) MeV and m_b(m_b) 4184(11) MeV. Adding our value of the gluon condensate with different previous estimates, we obtain the new sum rule average: <\alpha_s G^2>=(6.35+- 0.35) 10^-2 GeV^4. The mass-splittings M_\chi_0c(0b)-M_\eta_c(b) give @N2LO: \alpha_s(M_Z)=0.1183(19)(3) in good agreement with the world average (see more detailed discussions in the section: addendum). .

   hep-phhep-exhep-latnucl-thInt.J.Mod.Phys.A(2018)·93 citations
7. 07*

   A very Practical Guide to Light Front Holographic QCD

   Liping Zou🇨🇳 · H.G. Dosch🇩🇪

   The aim of these lectures is to convey a working knowledge of Light Front Holographic QCD and Supersymmetric Light Front Holographic QCD. We first give an overview of holographic QCD in general and then concentrate on the application of the holographic methods on QCD quantized in the light front form. We show how the implementation of the supersymmetric algebra fixes the interaction and how one can obtain hadron mass spectra with the minimal number of parameters. We also treat propagators and compare the holographic approach with other non-perturbative methods. In the last chapter we describe the application of Light Front Holographic QCD to electromagnetic form factors.

   hep-phhep-th24 citations
8. 08*

   Sivers Asymmetry in the pion induced Drell-Yan process at COMPASS within TMD factorization

   Xiaoyu Wang🇨🇳 · Zhun Lu🇨🇳

   We investigate the Sivers asymmetry in the pion-induced single polarized Drell-Yan process in the theoretical framework of the transverse momentum dependent factorization up to next-to-leading logarithmic order of QCD. Within the TMD evolution formalism of parton distribution functions, the recently extracted nonperturbative Sudakov form factor for the pion distribution functions as well as the one for the Sivers function of the proton are applied to numerically estimate the Sivers asymmetry in the ${\pi }^{-}p$ Drell-Yan at the kinematics of the COMPASS at CERN. In the low $b$ region, the Sivers function in $b$-space can be expressed as the convolution of the perturbatively calculable hard coefficients and the corresponding collinear correlation function, of which the Qiu-Sterman function is the most relevant one. The effect of the energy-scale dependence of the Qiu-Sterman function to the asymmetry is also studied. We find that our prediction on the Sivers asymmetries as functions of $x_p$, $x_{\pi }$, $x_F$ and $q_{\perp }$ is consistent with the recent COMPASS measurement.

   hep-phhep-exPRD(2018)·11 citations
9. 09*

   From inflation to cosmological electroweak phase transition with a complex scalar singlet

   Wei Cheng🇨🇳 · Ligong Bian🇨🇳

   In this work, we investigate the possibility to realize inflation and strong first order electroweak phase transitions(SFOEWPT) together with the relic density explanation. We studied the usual Higgs-portal real singlet dark matter model and the global U(1) breaking complex singlet model with the pseudoscalar being dark matter candidate. We focus on higher dark matter parameter regions due to the lower dark matter masses region are almost excluded by the current direct detection experiments except that of the so-called $Higgsfunnelregime$ with $m_{DM}\sim m_h/2$. In both models, the SFOEWPT can occur through two-step where the magnitude of the Higgs-singlet quartic couplings can account for the Higgs or singlet inflation. The usual Higgs-portal real singlet dark matter model can not address the correct relic density together with the explanation of inflation and SFOEWPT. With the complex singlet model, the correct relic density can also be obtained simultaneously when the mixing angle $0.1<\theta <0.2$ and the dark matter mass is $\sim 800$ GeV.

   hep-phastro-ph.COPRD(2018)·50 citations
10. 10*

    Estimating decay rate of $X^{\pm }(5568)\to B_s{\pi }^{\pm }$ while assuming them to be molecular states

    Hong-Wei Ke · Xue-Qian Li🇨🇳

    Discovery of $X(5568)$ brings up a tremendous interest because it is very special, i.e. made of four different flavors. The D0 collaboration claimed that they observed this resonance through portal $X(5568)\to B_s\pi$, but unfortunately, later the LHCb, CMS, CDF and ATLAS collaborations' reports indicate that no such state was found. Almost on the Eve of 2017, the D0 collaboration reconfirmed existence of $X(5568)$ via the semileptonic decay of $B_s$. To further reveal the discrepancy, supposing $X(5568)$ as a molecular state, we calculate the decay rate of $X(5568)\to B_s{\pi }^{+}$ in an extended light front model. Numerically, the theoretically predicted decay width of $\Gamma (X(5568)\to B_s{\pi }^{+})$ is $20.28$ MeV which is consistent with the result of the D0 collaboration ($\Gamma =18.6_{-6.1}^{+7.9}(stat{)}_{-3.8}^{+3.5}(syst)$ MeV). Since the resonance is narrow, signals might be drowned in a messy background. In analog, two open-charm molecular states $DK$ and $BD$ named as $X_a$ and $X_b$, could be in the same situation. The rates of $X_a\to D_s{\pi }^0$ and $X_b\to B_c{\pi }^0$ are estimated as about 30 MeV and 20 MeV respectively. We suggest the experimental collaborations round the world to search for these two modes and accurate measurements may provide us with valuable information.

    hep-phhep-exEPJC(2018)·12 citations
11. 11*

    Transverse-velocity scaling of femtoscopy in $\sqrt{s}=7$ TeV proton-proton collisions

    T. J. Humanic🇺🇸

    Although transverse-mass scaling of femtoscopic radii is found to hold to a good approximation in heavy-ion collision experiments, it is seen to fail for high-energy proton-proton collisions. It is shown that if invariant radius parameters are plotted versus the transverse velocity instead, scaling with the transverse velocity is seen in $\sqrt{s}=7$ TeV proton-proton experiments. A simple semi-classical model is shown to qualitatively reproduce this transverse velocity scaling.

    hep-phnucl-exJ.Phys.G(2018)·2 citations
12. 12*

    Analytic Neutrino Oscillation Probabilities in Matter: Revisited

    Stephen J. Parke🇺🇸 · Peter B. Denton🇩🇰 · Hisakazu Minakata🇪🇸

    We summarize our recent paper on neutrino oscillation probabilities in matter, explaining the importance, relevance and need for simple, highly accurate approximations to the neutrino oscillation probabilities in matter. Simple expressions for the neutrino mixing angles and mass squared differences in matter are given in an Appendix. Using these in the vacuum oscillation probabilities instead of the vacuum values, gives an excellent approximation to the oscillation probabilities in matter.

    hep-phhep-exPoS(2018)·7 citations
13. 13*

    On the clustering properties of produced particles in high-energy $pp$ collisions

    Cheuk-Yin Wong🇺🇸 · Hanpu Jiang🇺🇸 · Nanxi Yao🇺🇸 · Liwen Wen🇺🇸 · Gang Wang🇺🇸 · Huan Zhong Huang🇺🇸

    Minijets provide useful information on parton interactions in the low transverse-momentum (low-$p_T$) region. Because minijets produce clusters, we study the clustering properties of produced particles in high-energy $pp$ collisions as a first step to identify minijets. We develop an algorithm to find clusters by using the k-means clustering method, in conjunction with a k-number (cluster number) selection principle in the space of pseudorapidity and azimuthal angles. We test the clustering algorithm using events generated by PYTHIA 8.1, for $pp$ collision at $\sqrt{s}=200$ GeV. We find that clustering of low-$p_T$ hadrons occurs in high multiplicity events. However similar clustering properties are also present for particles produced randomly in a finite pseudorapidity and azimuthal angle space. To distinguish the dynamics from random generations of events, it is necessary to examine the correlation between particles and between clusters. We find that the correlations between clusters may provide a useful tool to distinguish the underlying dynamics of the reaction mechanism.

    hep-phhep-exnucl-exnucl-thPRD(2020)·4 citations
14. 14*

    Jet angularity measurements for single inclusive jet production

    Zhong-Bo Kang🇺🇸 · Kyle Lee🇺🇸 · Felix Ringer🇺🇸

    We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter $a$ allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semi-inclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.

    hep-phJHEP(2018)·46 citations
15. 15*

    Probing Electroweak Phase Transition via Enhanced Di-Higgs Production

    Marcela Carena🇺🇸 · Zhen Liu🇺🇸 · Marc Riembau🇪🇸

    We consider a singlet extension of the Standard Model (SM) with a spontaneous $Z_2$ breaking and study the gluon-gluon fusion production of the heavy scalar, with subsequent decay into a pair of SM-like Higgs bosons. We find that an on-shell interference effect can notably enhance the resonant di-Higgs production rate up to 40\%. In addition, consistently taking into account both the on-shell and off-shell interference effects between the heavy scalar and the SM di-Higgs diagrams significantly improves the HL-LHC and HE-LHC reach in this channel. As an example, within an effective field theory analysis in an explicitly $Z_2$ breaking scenario, we further discuss the potential to probe the parameter region compatible with a first order electroweak phase transition. Our analysis is applicable for general potentials of the singlet extension of the SM as well as for more general resonance searches.

    hep-phhep-exPRD(2018)·70 citations
16. 16*

    Looking for Minimal Inverse Seesaw scenarios at the LHC with Jet Substructure Techniques

    Akanksha Bhardwaj🇮🇳 · Arindam Das🇰🇷 · Partha Konar🇮🇳 · Arun Thalapillil🇮🇳

    Simple extensions of the Standard Model (SM) with additional Right Handed Neutrinos (RHNs) can elegantly explain the existence of small neutrino masses and their flavor mixings. Collider searches for sterile neutrinos are being actively pursued currently. Heavy RHNs may dominantly decay into $W^{\pm }{l}^{\pm }$ after being produced at the LHC. In this paper, we consider collider signatures of heavy pseudo-Dirac neutrinos in the context of inverse seesaw scenario, with a sizable mixing with the SM neutrinos under two different flavor structures, viz., Flavor Diagonal (FD) and Flavor Non-Diagonal (FND) scenarios. For the latter scenario we use a general parametrization for the model parameters by introducing an arbitrary orthogonal matrix and nonzero Dirac and Majorana phases. We then perform a parameter scan to identify allowed parameter regions which satisfy all experimental constraints. As an alternative channel to the traditional trilepton signature, we propose the opposite-sign di-lepton signature in the final state, in association with a fat jet from the hadronic decay of the boosted $W^{\pm }$ . We specifically consider a fat jet topology and explore the required enhancements from exploiting the characteristics of the jet substructure techniques. We perform a comprehensive collider analysis to demonstrate the effectiveness of this channel in both of the scenarios, significantly enhancing the bounds on the RHN mass and mixing angles at the 13 TeV LHC. Interestingly the FND scenario can reach up to a 5- $\sigma$ limit under the presence of the general parametrization at the high luminosity LHC.

    hep-phhep-exJ.Phys.G(2020)·46 citations
17. 17*

    Two-Loop master integrals for heavy-to-light form factors of two different massive fermions

    Long-Bin Chen🇨🇳

    We calculate the full set of the two-loop master integrals for heavy-to-light form factors of two different massive fermions for arbitrary momentum transfer in NNLO QCD or QED corrections. These integrals allow to determine the two-loop QCD or QED corrections to the amplitudes for heavy-to-light form factors of two massive fermions in a full analytical way, without any approximations. The analytical results of the master integrals are derived using the method of differential equations, along with a proper choosing of canonical basis for the master integrals. All the results of master integrals are expressed in terms of Goncharov polylogarithms.

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

    Bose-Einstein condensate and degenerate Fermi cored dark matter halos

    Wen-Jian Chung🇨🇦 · Lorne Nelson🇨🇦

    There has been considerable interest in the last several years in support of the idea that galaxies and clusters could have highly condensed cores of dark matter (DM) within their central regions. In particular, it has been suggested that dark matter could form Bose--Einstein condensates (BECs) or degenerate Fermi cores. We examine these possibilities under the assumption that the core consists of highly condensed DM (either bosons or fermions) that is embedded in a diffuse envelope (e.g., isothermal sphere). The novelty of our approach is that we invoke composite polytropes to model spherical collisionless structures in a way that is physically intuitive and can be generalized to include other equations of state (EOSs). Our model is very amenable to the analysis of BEC cores (composed of ultra-light bosons) that have been proposed to resolve small-scale CDM anomalies. We show that the analysis can readily be applied to bosons with or without small repulsive self-interactions. With respect to degenerate Fermi cores, we confirm that fermionic particle masses between 1 -- 1000 keV are not excluded by the observations. Finally, we note that this approach can be extended to include a wide range of EOSs in addition to multi-component collisionless systems.

    ↳ astro-ph.GAhep-phJCAP(2018)·4 citations
19. 19*

    Chiral plasma instability and primordial Gravitational wave

    Sampurn Anand🇮🇳 · Jitesh R. Bhatt🇮🇳 · Arun Kumar Pandey🇮🇳

    It is known that cosmic magnetic field, if present, can generate anisotropic stress in the plasma and hence, can act as a source of gravitational waves. These cosmic magnetic fields can be generated at very high temperature, much above electroweak scale, due to the gravitational anomaly in presence of the chiral asymmetry. The chiral asymmetry leads to instability in the plasma which ultimately leads to the generation of magnetic fields. In this article, we discuss the generation of gravitational waves, during the period of instability, in the chiral plasma sourced by the magnetic field created due to the gravitational anomaly. We have shown that such gravitational wave will have a unique spectrum. Moreover, depending on the temperature of the universe at the time of its generation, such gravitational waves can have a wide range of frequencies. We also estimate the amplitude and frequency of the gravitational waves and delineate the possibility of its detection by future experiments like eLISA.

    ↳ astro-ph.COgr-qchep-phphysics.plasm-phEPJC(2019)·18 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.