Fri·Feb 2, 2018Friday·February 2, 2018

1. 01*

   Polarization and dilepton angular distribution in pion-nucleon collisions

   Miklós Zétényi🇭🇺 · Enrico Speranza🇩🇪 · Bengt Friman🇩🇪

   We study hadronic polarization and the related anisotropy of the dilepton angular distribution for the reaction $\pi N\to N{e}^{+}{e}^{-}$. We employ consistent effective interactions for baryon resonances up to spin-5/2 to compute their contribution to the anisotropy coefficient. We show that the spin and parity of the intermediate baryon resonance is reflected in the angular dependence of the anisotropy coefficient. We present results for the anisotropy coefficient including the $N(1520)$ and $N(1440)$ resonances, which are essential at the collision energy of the recent data obtained by the HADES collaboration on this reaction. We conclude that the anisotropy coefficient provides useful constraints for unraveling the resonance contributions to this process.

   hep-phnucl-thFew Body Syst.(2018)·0 citations
2. 02*

   Impact of low-$x$ resummation on QCD analysis of HERA data

   xFitter Developers' team: Hamed Abdolmaleki🇮🇷 · Valerio Bertone🇳🇱 · Daniel Britzger🇩🇪 · Stefano Camarda🇨🇭 · Amanda Cooper-Sarkar🇬🇧 · Francesco Giuli🇬🇧 · Alexander Glazov🇩🇪 · Aleksander Kusina🇵🇱 · Agnieszka Luszczak🇵🇱 · Fred Olness🇺🇸 · Andrey Sapronov🇷🇺 · Pavel Shvydkin🇷🇺 and 3 other authors

   Fits to the final combined HERA deep-inelastic scattering cross-section data within the conventional DGLAP framework of QCD have shown some tension at low $x$ and low $Q^2$. A resolution of this tension incorporating $\ln (1/x)$-resummation terms into the HERAPDF fits is investigated using the xFitter program. The kinematic region where this resummation is important is delineated. Such high-energy resummation not only gives a better description of the data, particularly of the longitudinal structure function $F_L$, it also results in a gluon PDF which is steeply rising at low $x$ for low scales, $Q^2\simeq 2.5$ GeV${}^2$, contrary to the fixed-order NLO and NNLO gluon PDF.

   hep-phEPJC(2018)·135 citations
3. 03*

   Direct photon production in relativistic heavy-ion collisions -- a theory update

   Charles Gale🇨🇦

   For tomographic studies of relativistic nuclear collisions and of the quark-gluon plasma, photons (real and virtual) are unique. They are the only probes than can be both soft and penetrating. First we report on advances in modelling the hadron dynamics of heavy-ion collisions using a hybrid approach which consists of IP-Glasma, relativistic fluid dynamics, and hadronic cascade components. We briefly discuss the "photon flow puzzle", and then focus on a recent development in the theory of photon emission from a non-equilibrium, strongly interacting medium.

   hep-phnucl-exnucl-thPoS(2019)·10 citations
4. 04*

   Revisiting Final State Interaction in Charmless $B_q\to PP$ Decays

   Chun-Khiang Chua🇹🇼

   Various new measurements in charmless $B_{u,d,s}\to PP$ modes, where $P$ is a low lying pseudoscalar meson, are reported by Belle and LHCb. These include the rates of $B^0\to {\pi }^0{\pi }^0$, $\eta {\pi }^0$, $B_s\to {\eta }^{\prime }{\eta }^{\prime }$, $B^0\to K^{+}{K}^{-}$ and $B_s^0\to {\pi }^{+}{\pi }^{-}$ decays. Some of these modes are highly suppressed and are among the rarest $B$ decays. Direct CP asymmetries on various modes are constantly updated. It is well known that direct CP asymmetries and rates of suppressed modes are sensitive to final state interaction (FSI). As new measurements are reported and more data will be collected, it is interesting and timely to revisit the rescattering effects in $B_{u,d,s}\to PP$ states. We perform a ${\chi }^2$ analysis with all available data on CP-averaged rates and CP asymmetries in $\overline{B}{}_{u,d,s}\to PP$ decays. Our numerical results are compared to data and those from factorization approach. The quality of the fit is improved significantly from the factorization results in the presence of rescattering. The relations on topological amplitudes and rescattering are explored and they help to provide a better understanding of the effects of FSI. As suggested by U(3) symmetry on topological amplitudes and FSI, a vanishing exchange rescattering scenario is considered. The exchange, annihilation, $u$-penguin, $u$-penguin annihilation and some electroweak penguin amplitudes are enhanced significantly via annihilation and total annihilation rescatterings. In particular, the $u$-penguin annihilation amplitude is sizably enhanced by the tree amplitude via total annihilation rescattering. These enhancements affect rates and CP asymmetries. Predictions can be checked in the near future.

   hep-phhep-exPRD(2018)·9 citations
5. 05*

   Manifestation of Lepton Interaction Nonuniversality in Spontaneously Violated Mirror Symmetry

   Igor T. Dyatlov🇷🇺

   LHCb data indicate a significant difference in widths between the B->K (or K^*) + e^+ e^- and B->K (or K^*) + {\mu}^+ {\mu}^- decays (April 2017). The width of the e^+ e^--channel is noticeably larger than that of the {\mu}^+ {\mu}^--channel. SM-calculations require equality here. The difference may mean that a new interaction exists which changes generations and distinguishes leptons, with coupling constants much larger than, and inverse in power to, the SM-coupling of fermions with the Higgs boson. In the spontaneously violated mirror symmetry, the coupling between SM particles and the heavy (in principle) second Higgs scalar, necessarily present here, is characterized by precisely such properties. The inverse strong power of such a coupling is not an additional hypothesis but also a necessary condition for the qualitative reproduction of the observed mass hierarchy of charged leptons and the structure of lepton weak mixing, the PMNS matrix. In the mirror model being discussed, all properties, including the inverse power of the new interaction, are dictated by the hierarchical character of mass spectra for quarks and charged leptons.

   hep-phPhys.Atom.Nucl.(2018)·1 citation
6. 06*

   A method for model-independent measurement of the CKM angle $\beta$ via time-dependent analysis of the $B^0\to D{\pi }^{+}{\pi }^{-}$, $D\to K_S^0{\pi }^{+}{\pi }^{-}$ decays

   A. Bondar🇷🇺 · A. Kuzmin🇷🇺 · V. Vorobyev🇷🇺

   A new method for model-independent measurement of the CKM angle $\beta$ is proposed, that employs time-dependent analysis of flavour-tagged $B^0\to D{\pi }^{+}{\pi }^{-}$ decays with $D$ meson decays into CP-specific and~$K_S^0{\pi }^{+}{\pi }^{-}$ final states. This method can be used to measure the angle $\beta$ with future data from the Belle II and LHCb experiments with the precision level of one degree.

   hep-phphysics.atom-phJHEP(2018)·9 citations
7. 07*

   Finite volume effects with stationary wave solution from Nambu--Jona-Lasinio model

   Qing-Wu Wang · Yonghui Xia · Hong-Shi Zong

   In this paper, we use the two-flavor Nambu-Jona-Lasinio (NJL) model with the proper time regularization to study the finite-volume effects of QCD chiral phase transition. Within a cubic volume of finite size $L$, we choose the stationary wave condition (SWC) as the real physical spatial boundary conditions of quark fields and compare our results with that by means of commonly used (anti-)period boundary condition (APBC or PBC). It is found that the results by means of SWC are obviously different to the results from the APBC or PBC. Although the three boundary conditions give the same chiral crossover transition curve in the infinite volume limit, the limit size $L_0$ (when $L\ge L_0$, the chiral quark condensate $-{⟨\bar{\psi }\psi ⟩}_L$ is indistinguishable from that at $L=\infty$) using SWC is $L_0\approx 500$ fm which is much larger than the results obtained using APBC or PBC. More importantly, $L_0\approx 500$ fm is also much large than the typical size of the quark-gluon plasma produced by the relativistic heavy ion collisions. This means that the finite volume effects play a very important role in Relativistic Heavy Ion Collisions. In addition, we also found that when $L\le 2$ fm, even at zero temperature the chiral symmetry is effectively restored. Furthermore, to quantitatively reflect the finite volume effects on the QCD chiral phase transition, we introduce a new vacuum susceptibility, ${\chi }_{1/L}(T)=-\frac{\partial ⟨\bar{\psi }\psi ⟩}{\partial (1/L)}$. With this new vacuum susceptibility, it is very interesting to find ${\chi }_{1/L}(T=0)={\chi }_{1/L}(T=1/L)$ for SWC.

   hep-ph12 citations
8. 08*

   Quark mass functions and pion structure in the Covariant Spectator Theory

   E. P. Biernat🇵🇹 · F. Gross🇺🇸 · M. T. Peña🇵🇹 · A. Stadler🇵🇹 · S. Leitão🇵🇹

   The Covariant Spectator Theory is applied to the description of quarks and the pion. The dressed quark mass function is calculated dynamically in Minkowski space and used in the calculation of the pion electromagnetic form factor. The effects of the mass function on the pion form factor and the different quark-pole contributions to the triangle diagram are analyzed.

   hep-phnucl-thFew Body Syst.(2018)·2 citations
9. 09*

   NLO QCD corrections to Higgs boson plus jet production with full top-quark mass dependence

   S. P. Jones🇩🇪 · M. Kerner🇩🇪 · G. Luisoni🇩🇪

   We present the next-to-leading order QCD corrections to the production of a Higgs boson in association with one jet at the LHC including the full top-quark mass dependence. The mass of the bottom quark is neglected. The two-loop integrals appearing in the virtual contribution are calculated numerically using the method of Sector Decomposition. We study the Higgs boson transverse momentum distribution, focusing on the high $p_{t,\mathrm{H}}$ region, where the top-quark loop is resolved. We find that the next-to-leading order QCD corrections are large but that the ratio of the next-to-leading order to leading order result is similar to that obtained by computing in the limit of large top-quark mass.

   hep-phhep-exPRL(2018)·154 citations
10. 10*

    Multiparticle azimuthal cumulants in p+Pb collisions from a multiphase transport model

    Mao-Wu Nie🇨🇳 · Peng Huo🇺🇸 · Jiangyong Jia🇺🇸 · Guo-Liang Ma🇨🇳

    A new subevent cumulant method was recently developed, which can significantly reduce the non-flow contributions in long-range correlations for small systems compared to the standard cumulant method. In this work, we study multi-particle cumulants in $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with a multiphase transport model (AMPT), including two- and four-particle cumulants ($c_2\{2\}$ and $c_2\{4\}$) and symmetric cumulants [SC(2, 3) and SC(2, 4)]. Our numerical results show that $v_2\{2\}$ is consistent with the experimental data, while the magnitude of $c_2\{4\}$ is smaller than the experimental data, which may indicate either the collectivity is underestimated or some dynamical fluctuations are absent in the AMPT model. For the symmetric cumulants, we find that the results from the standard cumulant method are consistent with the experimental data, but those from the subevent cumulant method show different behaviors. The results indicate that the measurements from the standard cumulant method are contaminated by non-flow effects, especially when the number of produced particles is small. The subevent cumulant method is a better tool to explore the $real$ collectivity in small systems.

    hep-phnucl-exnucl-thPRC(2018)·30 citations
11. 11*

    Higgs-boson decay to four fermions in the Two-Higgs-Doublet Model and Prophecy4f

    Lukas Altenkamp🇩🇪 · Stefan Dittmaier🇩🇪 · Heidi Rzehak🇩🇰

    We present the next-to-leading-order calculation of the partial decay widths of the light CP-even Higgs boson decaying into four fermions in the Two-Higgs-Doublet Model. The four different renormalization schemes applied in the calculation are described as well as the calculation and its implementation into the analysis tool Prophecy4f. Some sample results show the size of the next-to-leading-order correction as well as the overall size of the deviation from the Standard Model prediction.

    hep-ph0 citations
12. 12*

    Trimaximal mixing with a texture zero

    Radha Raman Gautam🇮🇳

    We analyze neutrino mass matrices having one texture zero, assuming that the neutrino mixing matrix has either its first (TM${}_1$) or second (TM${}_2$) column identical to that of the tribimaximal mixing matrix. We found that all the six possible one texture zero neutrino mass matrices are compatible with the present neutrino oscillation data when combined with TM${}_1$ or TM${}_2$ mixing. These textures have interesting predictions for the presently unknown parameters such as the effective Majorana neutrino mass, the Dirac CP violating phase and the neutrino mass scale. We also present a way to theoretically realize some of these textures using $A_4$ symmetry within the framework of type-I+II seesaw mechanism.

    hep-phPRD(2018)·28 citations
13. 13*

    New NLOPS predictions for $\mathbf{t}\bar{\mathbf{t}}+\mathbf{b}$-jet production at the LHC

    Tomáš Ježo🇨🇭 · Jonas M. Lindert🇬🇧 · Niccolo Moretti🇨🇭 · Stefano Pozzorini🇨🇭

    Measurements of $t\bar{t}H$ production in the $H\to b\bar{b}$ channel depend in a critical way on the theoretical uncertainty associated with the irreducible $t\bar{t}+b$-jet background. In this paper, analysing the various topologies that account for $b$-jet production in association with a $t\bar{t}$ pair, we demonstrate that the process at hand is largely driven by final-state $g\to b\bar{b}$ splittings. We also show that in five-flavour simulations based on $t\bar{t}+$multi-jet merging $b$-jet production is mostly driven by the parton shower, while matrix elements play only a marginal role in the description of $g\to b\bar{b}$ splittings. Based on these observations we advocate the use of NLOPS simulations of $pp\to t\bar{t}b\bar{b}$ in the four-flavour scheme, and we present a new POWHEG generator of this kind. Predictions and uncertainties for $t\bar{t}+b$-jet observables at the 13 TeV LHC are presented both for the case of stable top quarks and with spin-correlated top decays. Besides QCD scale variations we consider also theoretical uncertainties related to the POWHEG matching method and to the parton shower modelling, with emphasis on $g\to b\bar{b}$ splittings. In general, matching and shower uncertainties turn out to be remarkably small. This is confirmed also by a tuned comparison against Sherpa+OpenLoops.

    hep-phhep-exEPJC(2018)·171 citations
14. 14*

    Decay of standard model-like Higgs boson $h\to \mu \tau$ in a 3-3-1 model with inverse seesaw neutrino masses

    T. Phong Nguyen🇻🇳 · T.Thuy Le🇻🇳 · T.T. Hong🇻🇳 · L.T. Hue🇻🇳

    By adding new gauge singlets of neutral leptons, the improved versions of the 3-3-1 models with right-handed neutrinos have been recently introduced in order to explain recent experimental neutrino oscillation data through the inverse seesaw mechanism. We prove that these models predict promising signals of lepton-flavor-violating decays of the standard-model-like Higgs boson $h_1^0\to \mu \tau ,e\tau$, which are suppressed in the original versions. One-loop contributions to these decay amplitudes are introduced in the unitary gauge. Based on a numerical investigation, we find that the branching ratios of the decays $h_1^0\to \mu \tau ,e\tau$ can reach values of $10^{-5}$ in the regions of parameter space satisfying the current experimental data of the decay $\mu \to e\gamma$. The value of $10^{-4}$ appears when the Yukawa couplings of leptons are close to the perturbative limit. Some interesting properties of these regions of parameter space are also discussed.

    hep-phPRD(2018)·42 citations
15. 15*

    Higgscitement: Cosmological Dynamics of Fine Tuning

    Mustafa A. Amin🇺🇸 · JiJi Fan🇺🇸 · Kaloian D. Lozanov🇩🇪 · Matthew Reece🇺🇸

    The Higgs potential appears to be fine-tuned, hence very sensitive to values of other scalar fields that couple to the Higgs. We show that this feature can lead to a new epoch in the early universe featuring violent dynamics coupling the Higgs to a scalar modulus. The oscillating modulus drives tachyonic Higgs particle production. We find a simple parametric understanding of when this process can lead to rapid modulus fragmentation, resulting in gravitational wave production. A nontrivial equation-of-state arising from the nonlinear dynamics also affects the time elapsed from inflation to the CMB, influencing fits of inflationary models. Supersymmetric theories automatically contain useful ingredients for this picture.

    hep-phastro-ph.COPRD(2019)·51 citations
16. 16*

    The Constructive Standard Model: Part I

    Neil Christensen🇺🇸 · Bryan Field🇺🇸

    In this paper, we construct the complete set of minimal 3-point vertices for the massive Standard Model (SM) based purely on symmetry principles, mass dimension and high-energy behavior and without any recourse to field theory, gauge symmetries or Feynman rules. Because the gravitational vertices are no more challenging than any other vertices in this constructive method, we include them as well. We also calculate the high-energy behavior of these vertices and compare with the well-known massless vertices, both as a check and as a way to pin down the normalization constants. We include all these vertices in tables as a reference for future investigations.

    hep-phhep-thPRD(2018)·49 citations
17. 17*

    Next-to-leading-logarithmic power corrections for $N$-jettiness subtraction in color-singlet production

    Radja Boughezal🇺🇸 · Andrea Isgrò🇺🇸 · Frank Petriello🇺🇸

    We present a detailed derivation of the power corrections to the factorization theorem for the 0-jettiness event shape variable $\mathcal{T}$. Our calculation is performed directly in QCD without using the formalism of effective field theory. We analytically calculate the next-to-leading logarithmic power corrections for small $\mathcal{T}$ at next-to-leading order in the strong coupling constant, extending previous computations which obtained only the leading-logarithmic power corrections. We address a discrepancy in the literature between results for the leading-logarithmic power corrections to a particular definition of 0-jettiness. We present a numerical study of the power corrections in the context of their application to the $N$-jettiness subtraction method for higher-order calculations, using gluon-fusion Higgs production as an example. The inclusion of the next-to-leading-logarithmic power corrections further improves the numerical efficiency of the approach beyond the improvement obtained from the leading-logarithmic power corrections.

    hep-phPRD(2018)·89 citations
18. 18*

    Structure of the orbital excited $N^{\ast }$ from the Schwinger-Dyson equations

    K. Raya🇲🇽 · L.X. Gutiérrez🇲🇽 · A. Bashir🇲🇽

    We present progress in the evaluation of ${\gamma }^{\ast }N\to N^{\ast }(1535)$ transition form factors in a quark-diquark picture of these baryons. Our analysis is based upon the fully-consistent treatment of a vector $\times$ vector contact interaction, embedded in the interlaced formalism of Schwinger-Dyson and Bethe-Salpeter equations.

    ↳ nucl-thhep-phFew Body Syst.(2018)·6 citations
19. 19*

    Phenomenology of anomalous chiral transports in heavy-ion collisions

    Xu-Guang Huang🇨🇳

    High-energy Heavy-ion collisions can generate extremely hot quark-gluon matter and also extremely strong magnetic fields and fluid vorticity. Once coupled to chiral anomaly, the magnetic fields and fluid vorticity can induce a variety of novel transport phenomena, including the chiral magnetic effect, chiral vortical effect, etc. Some of them require the environmental violation of parity and thus provide a means to test the possible parity violation in hot strongly interacting matter. We will discuss the underlying mechanism and implications of these anomalous chiral transports in heavy-ion collisions.

    ↳ nucl-thhep-phnucl-exEPJ Web Conf.(2018)·1 citation
20. 20*

    Hadron Collider Searches for Diboson Resonances

    Tommaso Dorigo🇮🇹

    This review covers results of searches for new elementary particles that decay into boson pairs (dibosons), performed at the CERN Large Hadron Collider in proton-proton collision data collected by the ATLAS and CMS experiments at 7-, 8-, and 13-TeV center-of-mass energy until the year 2017. The available experimental results of the analysis of final states including most of the possible two-object combinations of W and Z bosons, photons, Higgs bosons, and gluons place stringent constraints on a variety of theoretical ideas that extend the standard model, pushing into the multi-TeV region the scale of allowed new physics phenomena.

    ↳ hep-exhep-phPPNP(2018)·20 citations
21. 21*

    Anisotropic flow: A case for Bottomonia

    Debasish Das (1) · Nirupam Dutta (2) ((1) SINP · (2) NISER)

    Studies of $J/$$\psi$ $v_2$ at RHIC and LHC energies have provided important elements towards the understanding on the production mechanisms and on the thermalization of charm quarks. Bottomonia has an advantage since it is a cleaner probe. A brief discussion has been provided for ${\rm Y}(1S)$ $v_2$, which can become the new probe for QGP, including the necessity of studies for small systems.

    ↳ nucl-exhep-exhep-phnucl-thInt.J.Mod.Phys.A(2018)·11 citations
22. 22*

    TikZ-FeynHand: Basic User Guide

    Max Dohse🇲🇽

    This is a userguide for the LaTex package Tikz-FeynHand at https://ctan.org/pkg/tikz-feynhand which let's you draw Feynman diagrams using TikZ. It contains many examples and a 5-minute introduction to TikZ. The package is a low-end modification of the package TikZ-Feynman at https://ctan.org/pkg/tikz-feynman, one of whose principal advantages is the automatic generation of diagrams, for which it needs LuaTex. FeynHand only provides the manual mode and hence runs in LaTex without any reference to LuaTex. In addition it provides some NEW STYLES for vertices and propagators, alternative SHORTER KEYWORDS in addition to TikZ-Feynman's longer ones, some shortcut commands for QUICKLY CUSTOMIZING the diagrams' look, and the new feature to put one propagator "ON TOP" of another.

    ↳ cs.OHhep-phhep-th31 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.