Fri·Apr 7, 2017Friday·April 7, 2017

1. 01*

   Disentangling weak and strong interactions in $B\to K^{\ast }(\to K\pi )\pi$ Dalitz-plot analyses

   J. Charles🇫🇷 · S. Descotes-Genon🇫🇷 · J. Ocariz🇫🇷 · A. Pérez Pérez🇪🇸

   Dalitz-plot analyses of $B\to K\pi \pi$ decays provide direct access to decay amplitudes, and thereby weak and strong phases can be disentangled by resolving the interference patterns in phase space between intermediate resonant states. A phenomenological isospin analysis of $B\to K^{\ast }(\to K\pi )\pi$ decay amplitudes is presented exploiting available amplitude analyses performed at the Babar, Belle and LHCb experiments. A first application consists in constraining the CKM parameters thanks to an external hadronic input. A method, proposed some time ago by two different groups and relying on a bound on the electroweak penguin contribution, is shown to lack the desired robustness and accuracy, and we propose a more alluring alternative using a bound on the annihilation contribution. A second application consists in extracting information on hadronic amplitudes assuming the values of the CKM parameters from a global fit to quark flavour data. The current data yields several solutions, which do not fully support the hierarchy of hadronic amplitudes usually expected from theoretical arguments (colour suppression, suppression of electroweak penguins), as illustrated from computations within QCD factorisation. Some prospects concerning the impact of future measurements at LHCb and Belle II are also presented. Results are obtained with the CKMfitter analysis package, featuring the frequentist statistical approach and using the Rfit scheme to handle theoretical uncertainties.

   hep-phhep-exEPJC(2017)·13 citations
2. 02*

   An approach to QCD perturbative and non-perturbative beta functions

   Renata Jora🇷🇴

   Using the global properties of the QCD partition function we determine an all order perturbative beta function in the background gauge field method to find out that it has a simple expressions whose properties and consequences align with other recent results in the QCD literature. We further compute the non-perturbative beta functions for the coupling constant and the theta angle in the background of an instanton field with winding number $n$. We solve for the theta angle in the non-perturbative region to determine that it is approximately zero. By extrapolating to the full QCD beta functions our result may constitute a solution to the strong CP problem.

   hep-ph1 citation
3. 03*

   Theory update on the inlcusive determination of $|V_{cb}|$

   Soumitra Nandi🇮🇳

   In this talk I update the precision determination of the CKM element $|V_{cb}|$ from the inclusive decay $B\to X_c\ell {\nu }_{\ell }$.

   hep-phhep-exPoS(2017)·1 citation
4. 04*

   Soft-gluon resolution scale in QCD evolution equations

   F. Hautmann🇬🇧 · H. Jung🇩🇪 · A. Lelek🇩🇪 · V. Radescu🇨🇭 · R. Zlebcik🇩🇪

   QCD evolution equations can be recast in terms of parton branching processes. We present a new numerical solution of the equations. We show that this parton-branching solution can be applied to analyze infrared contributions to evolution, order-by-order in the strong coupling ${\alpha }_s$, as a function of the soft-gluon resolution scale parameter. We examine the cases of transverse-momentum ordering and angular ordering. We illustrate that this approach can be used to treat distributions which depend both on longitudinal and on transverse momenta.

   hep-phPLB(2017)·170 citations
5. 05*

   Interference phenomena in the decay $D_s^{+}\to \eta {\pi }^0{\pi }^{+}$ induced by the $a_0^0(980)-f_0(980)$ mixing

   N.N. Achasov🇷🇺 · G.N. Shestakov🇷🇺

   Using the data on the decay $D_s^{+}\to f_0(980){\pi }^{+}\to K^{+}{K}^{-}{\pi }^{+}$, we estimate the amplitude of the process $D_s^{+}\to \left[f_0(980)\to (K^{+}{K}^{-}+K^0{\bar{K}}^0)\to a_0^0(980)\right]{\pi }^{+}\to \eta {\pi }^0{\pi }^{+}$, caused by the mixing of $a_0^0(980)$ and $f_0(980)$ resonances that breaks the isotopic invariance due to the $K^{+}$ and $K^0$ meson mass difference. Effects of the interference of this amplitude with the amplitudes of the main mechanisms responsible for the decay $D_s^{+}\to \eta {\pi }^0{\pi }^{+}$ are analyzed. As such mechanisms, we examine the transition $D_s^{+}\to \eta {\rho }^{+}\to \eta {\pi }^0{\pi }^{+}$, which is observed in experiment, and the possible transition $D_s^{+}\to \left(a_0^0(980){\pi }^{+}+a_0^{+}(980){\pi }^0\right)\to \eta {\pi }^0{\pi }^{+}$. It is shown that the rapidly varying phase of the $a_0^0(980)-f_0(980)$ transition amplitude strongly influences on the interference curves.

   hep-phhep-exnucl-thPRD(2017)·21 citations
6. 06*

   Momentum Distribution and Correlation due to mass difference caused by power-like distribution

   Masamichi Ishihara🇯🇵

   The momentum distribution and particle correlation due to the mass difference were studied both in the case of the conventional expectation value and in the case of $q$-expectation value, when the momentum distribution is described by a Tsallis distribution with the entropic parameter $q\ge 1$. The magnitude of the momentum distribution for hard modes increases as $q$ increases, and the $q$-dependence of the momentum distribution is quite weak for soft modes. The correlation at $q>1$ is larger than that at $q=1$ for soft modes, while the correlation at $q>1$ is smaller than that at $q=1$ for hard modes. The $q$-dependence of these quantities in the case of $q$-expectation value is weaker than that in the case of the conventional expectation value, respectively.

   hep-phIJMPE(2017)·4 citations
7. 07*

   Top quark electroweak couplings at future lepton colliders

   Christoph Englert🇬🇧 · Michael Russell🇬🇧

   We perform a comparative study of the reach of future $e^{+}{e}^{-}$ collider options for the scale of non-resonant new physics effects in the top quark sector, phrased in the language of higher-dimensional operators. Our focus is on the electroweak top quark pair production process $e^{+}{e}^{-}\to Z^{\ast }/\gamma \to t\bar{t}$, and we study benchmark scenarios at the ILC and CLIC. We find that both are able to constrain mass scales up to the few TeV range in the most sensitive cases, improving by orders of magnitude on the forecasted capabilities of the LHC. We discuss the role played by observables such as forward-backward asymmetries, and making use of different beam polarisation settings, and highlight the possibility of lifting a degeneracy in the allowed parameter space by combining top observables with precision $Z$-pole measurements from LEP1.

   hep-phEPJC(2017)·42 citations
8. 08*

   Glueball dark matter in non-standard cosmologies

   Bobby Samir Acharya🇬🇧 · Malcolm Fairbairn🇬🇧 · Edward Hardy🇮🇹

   Hidden sector glueball dark matter is well motivated by string theory, compactifications of which often have extra gauge groups uncoupled to the visible sector. We study the dynamics of glueballs in theories with a period of late time primordial matter domination followed by a low final reheating temperature due to a gravitationally coupled modulus. Compared to scenarios with a high reheating temperature, the required relic abundance is possible with higher hidden sector confinement scales, and less extreme differences in the entropy densities of the hidden and visible sectors. Both of these can occur in string derived models, and relatively light moduli are helpful for obtaining viable phenomenology. We also study the effects of hidden sector gluinos. In some parts of parameter space these can be the dominant dark matter component, while in others their abundance is much smaller than that of glueballs. Finally, we show that heavy glueballs produced from energy in the hidden sector prior to matter domination can have the correct relic abundance if they are sufficiently long lived.

   hep-phhep-thJHEP(2017)·66 citations
9. 09*

   Analysis of the ${\Omega }_c(3000)$, ${\Omega }_c(3050)$, ${\Omega }_c(3066)$, ${\Omega }_c(3090)$ and ${\Omega }_c(3119)$ with QCD sum rules

   Zhi-Gang Wang🇨🇳

   In this article, we assign the ${\Omega }_c(3000)$, ${\Omega }_c(3050)$, ${\Omega }_c(3066)$, ${\Omega }_c(3090)$ and ${\Omega }_c(3119)$ to be the P-wave baryon states with $J^P={\frac{1}{2}}^{-}$, ${\frac{1}{2}}^{-}$, ${\frac{3}{2}}^{-}$, ${\frac{3}{2}}^{-}$ and ${\frac{5}{2}}^{-}$, respectively, and study them with the QCD sum rules by introducing an explicit relative P-wave between the two $s$ quarks. The predictions support assigning the ${\Omega }_c(3050)$, ${\Omega }_c(3066)$, ${\Omega }_c(3090)$ and ${\Omega }_c(3119)$ to be the P-wave baryon states with $J^P={\frac{1}{2}}^{-}$, ${\frac{3}{2}}^{-}$, ${\frac{3}{2}}^{-}$ and ${\frac{5}{2}}^{-}$, respectively, where the two $s$ quarks are in relative P-wave; while the ${\Omega }_c(3000)$ can be assigned to the P-wave baryon state with $J^P={\frac{1}{2}}^{-}$, where the two $s$ quarks are in relative S-wave.

   hep-phEPJC(2017)·82 citations
10. 10*

    Scattering unitarity with effective dimension-6 operators

    Swagata Ghosh🇮🇳 · Rashidul Islam🇮🇳 · Anirban Kundu🇮🇳

    The effects of physics beyond the Standard Model may be parametrized by a set of higher-dimensional operators leading to an effective theory. The introduction of these operators makes the theory nonrenormalizable, and one may reasonably expect a violation of unitarity in $2\to 2$ scattering processes,depending on the values of the Wilson coefficients of the higher dimensional operators. Bounds on these coefficients may be obtained from demanding that there be no such unitarity violation below the scale of the effective theory. We show, at the lowest level, how the new operators affect the scattering amplitudes with longitudinal gauge bosons, scalars, and $t\bar{t}$ in the final state, and find that one may expect a violation of unitarity even at the LHC energies with small values of some of the new Wilson coefficients. For most of the others, such a violation needs large coefficients, indicating nonperturbative physics for the ultraviolet-complete theory, although a proper treatment necessitates the inclusion of even higher-dimensional operators. However, deviations from the Standard Model expectations may be observed with even smaller values for these coefficients. We find that $WW\to WW$, $WW\to ZZ$, and $ZZ\to hh$ scatterings are the best possible channels to probe unitarity violations.

    hep-phJ.Phys.G(2018)·5 citations
11. 11*

    Hadronic vacuum polarization in $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$ process bellow 3 GeV

    Vladimir Sauli🇨🇿

    The interference effect between leptonic radiative corrections and hadronic polarization functions is calculated via optical theorem for $\mu -$pair productions. It is achieved within the use of the last data for ${\sigma }_h(e^{+}{e}^{-}\to hadrons)$ from SND,CMD,CMD-2,BABAR and BESSIII experimental Collaborations. The paper takes into account specific experimental conditions and the result is compared with KLOE experiment for ${\mu }^{-}{\mu }^{+}$ production at $\varphi$ meson energy. Small, but non-negligible tension between theory and experiment is discussed.

    hep-phhep-exActa Phys.Polon.Supp.(2017)·5 citations
12. 12*

    Milli-charged fermion vacuum polarization in cosmic magnetic fields and generation of CMB elliptic polarization

    Damian Ejlli🇷🇺

    The contribution of one loop milli-charged fermion vacuum polarization in cosmic magnetic field to the cosmic microwave background (CMB) polarization is considered. Exact and perturbative solution of the density matrix equations of motion in terms of the Stokes parameters are presented. For linearly polarized CMB at decoupling time, it is shown that propagation of CMB photons in cosmic magnetic field would generate elliptic polarization (circular and linear) of the CMB due to milli-charged fermion vacuum polarization. Analytic expressions for the degree of circular polarization and rotation angle of polarization plane of the CMB are presented. Depending on the ratio of milli-charged fermion relative charge to mass, $ϵ/m_{ϵ}$, and CMB observation frequency, it is shown that the acquired CMB degree of circular polarization could be of the order of magnitude $P_C(T_0)\sim 10^{-10}-10^{-6}$ in the best scenario. The effect studied generates CMB polarization even in the case when the CMB is initially in thermal equilibrium. Limits on the magnetic field amplitude due to prior decoupling CMB polarization are presented.

    hep-phastro-ph.COhep-thPRD(2017)·15 citations
13. 13*

    Exploring Spin-3/2 Dark Matter with Effective Higgs Couplings

    Chia-Feng Chang🇹🇼 · Xiao-Gang He🇨🇳 · Jusak Tandean🇹🇼

    We study an economical model of weakly-interacting massive particle dark matter (DM) which has spin 3/2 and interacts with the 125-GeV Higgs boson via effective scalar and pseudoscalar operators. We apply constraints on the model from the relic density data, LHC measurements of the Higgs boson, and direct and indirect searches for DM, taking into account the effective nature of the DM-Higgs couplings. We show that this DM is currently viable in most of the mass region from about 58 GeV to 2.3 TeV and will be probed more stringently by ongoing and upcoming experiments. Nevertheless, the presence of the DM-Higgs pseudoscalar coupling could make parts of the model parameter space elusive from future tests. We find that important aspects of this scenario are quite similar to those of its more popular spin-1/2 counterpart.

    hep-phhep-exPRD(2017)·24 citations
14. 14*

    ZA production in vector-boson scattering at next-to-leading order QCD

    Francisco Campanario🇪🇸 · Matthias Kerner🇩🇪 · Dieter Zeppenfeld🇩🇪

    Cross sections and differential distributions for ZA production in association with two jets via vector boson fusion are presented at next-to-leading order in QCD. The leptonic decays of the Z boson with full off-shell effects and spin correlations are taken into account. The uncertainties due to different scale choices and pdf sets are studied. Furthermore, we analyze the effect of including anomalous quartic gauge couplings at NLO QCD.

    hep-phhep-exJHEP(2018)·12 citations
15. 15*

    A global view on the Higgs self-coupling

    Stefano Di Vita🇩🇪 · Christophe Grojean🇩🇪 · Giuliano Panico🇪🇸 · Marc Riembau🇪🇸 · Thibaud Vantalon🇩🇪

    The Higgs self-coupling is notoriously intangible at the LHC. It was recently proposed to probe the trilinear Higgs interaction through its radiative corrections to single-Higgs processes. This approach however requires to disentangle these effects from those associated to deviations of other Higgs-couplings to fermions and gauge bosons. We show that a global fit exploiting only single-Higgs inclusive data suffers from degeneracies that prevent one from extracting robust bounds on each individual coupling. We show how the inclusion of double-Higgs production via gluon fusion, and the use of differential measurements in the associated single-Higgs production channels WH, ZH and ttH, can help to overcome the deficiencies of a global Higgs-couplings fit. In particular, we bound the variations of the Higgs trilinear self-coupling relative to its SM value to the interval [0.1, 2.3] at 68% confidence level at the high-luminosity LHC, and we discuss the robustness of our results against various assumptions on the experimental uncertainties and the underlying new physics dynamics. We also study how to obtain a parametrically enhanced deviation of the Higgs self-couplings and we estimate how large this deviation can be in a self-consistent effective field theory framework.

    hep-phhep-exJHEP(2017)·169 citations
16. 16*

    Illuminating Light Bending

    N.E.J. Bjerrum-Bohr🇩🇰 · Barry R. Holstein🇺🇸 · John F. Donoghue🇺🇸 · Ludovic Planté🇫🇷 · Pierre Vanhove🇫🇷

    The interactions of gravitons with spin-1 matter are calculated in parallel with the well known photon case. It is shown that graviton scattering amplitudes can be factorized into a product of familiar electromagnetic forms, and cross sections for various reactions are straightforwardly evaluated using helicity methods. Universality relations are identified. Extrapolation to zero mass yields scattering amplitudes for photon-graviton and graviton-graviton scattering. The phenomenon of light bending near a massive object, which is generally treated using classical general relativity, is discussed from alternative points of view.

    ↳ gr-qchep-phhep-thPoS(2017)·37 citations
17. 17*

    Testing backreaction effects with observational Hubble parameter data

    Shu-Lei Cao🇨🇳 · Huan-Yu Teng🇨🇳 · Hao-Ran Yu🇨🇳 · Hao-Yi Wan🇨🇳 · Tong-Jie Zhang🇨🇳

    In order to explore the generic properties of a backreaction model for explaining the accelerated expansion of the Universe, we exploit two metrics to describe the late time Universe. Since the standard FLRW metric cannot precisely describe the late time Universe on small scales, the template metric with an evolving curvature parameter ${\kappa }_{\mathcal{D}}(t)$ is employed. However, we doubt the validity of the prescription for ${\kappa }_{\mathcal{D}}$, which motivates us apply observational Hubble parameter data (OHD) to constrain parameters in dust cosmology. First, for FLRW metric, by getting best-fit constraints of ${\Omega }_m^{{\mathcal{D}}_0}=0.25_{-0.03}^{+0.03}$, $n=0.02_{-0.66}^{+0.69}$, and $H_{{\mathcal{D}}_0}=70.54_{-3.97}^{+4.24}\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$, the evolutions of parameters are explored. Second, in template metric context, by marginalizing over $H_{{\mathcal{D}}_0}$ as a prior of uniform distribution, we obtain the best-fit values of $n=-1.22_{-0.41}^{+0.68}$ and ${\Omega }_m^{{\mathcal{D}}_0}=0.12_{-0.02}^{+0.04}$. Moreover, we utilize three different Gaussian priors of $H_{{\mathcal{D}}_0}$, which result in different best-fits of $n$, but almost the same best-fit value of ${\Omega }_m^{{\mathcal{D}}_0}\sim 0.12$. Also, the absolute constraints without marginalization of parameter are obtained: $n=-1.1_{-0.50}^{+0.58}$ and ${\Omega }_m^{{\mathcal{D}}_0}=0.13\pm 0.03$. With these constraints, the evolutions of the effective deceleration parameter $q^{\mathcal{D}}$ indicate that the backreaction can account for the accelerated expansion of the Universe without involving extra dark energy component in the scaling solution context. Nevertheless, the results also verify that the prescription of ${\kappa }_{\mathcal{D}}$ is insufficient and should be improved.

    ↳ astro-ph.COgr-qchep-phhep-thEPJC(2018)·12 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.