Thu·Apr 27, 2017Thursday·April 27, 2017

1. 01*

   Minimal Fundamental Partial Compositeness

   Giacomo Cacciapaglia🇫🇷 · Helene Gertov🇩🇰 · Francesco Sannino🇩🇰 · Anders Eller Thomsen🇩🇰

   Building upon the fundamental partial compositeness framework we provide consistent and complete composite extensions of the standard model. These are used to determine the effective operators emerging at the electroweak scale in terms of the standard model fields upon consistently integrating out the heavy composite dynamics. We exhibit the first effective field theories matching these complete composite theories of flavour and analyse their physical consequences for the third generation quarks. Relations with other approaches, ranging from effective analyses for partial compositeness to extra dimensions as well as purely fermionic extensions, are briefly discussed. Our methodology is applicable to any composite theory of dynamical electroweak symmetry breaking featuring a complete theory of flavour.

   hep-phPRD(2018)·31 citations
2. 02*

   High energy behaviour of form factors

   Taushif Ahmed🇩🇪 · Johannes M. Henn🇩🇪 · Matthias Steinhauser🇩🇪

   We solve renormalization group equations that govern infrared divergences of massless and massive form factors. By comparing to recent results for planar massive three-loop and massless four-loop form factors in QCD, we give predictions for the high-energy limit of massive form factors at the four- and for the massless form factor at five-loop order. Furthermore, we discuss the relation which connects infrared divergences regularized dimensionally and via a small quark mass and extend results present in the literature to higher order.

   hep-phhep-thJHEP(2017)·33 citations
3. 03*

   Discovery prospects of a light Higgs boson at the LHC in type-I 2HDM

   Disha Bhatia🇮🇳 · Ushoshi Maitra🇮🇳 · Saurabh Niyogi🇮🇳

   We present a comprehensive analysis of observing a light Higgs boson in the mass range $70$ -- $110$ GeV at the 13/14 TeV LHC, in the context of the type-I two-Higgs-doublet model. The decay of the light Higgs to a pair of bottom quarks is dominant in most parts of the parameter space, except in the fermiophobic limit. Here its decay to bosons, (mainly a pair of photons), becomes important. We perform an extensive collider analysis for the $b\bar{b}$ and $\gamma \gamma$ final states. The light scalar is tagged in the highly boosted regimes for the $b\bar{b}$ mode to reduce the enormous QCD background. This decay can be observed with a few thousand fb${}^{-1}$ of integrated luminosity at the LHC. Near the fermiophobic limit, the decay of the light Higgs to a pair of photons can even be probed with a few hundred fb${}^{-1}$ of integrated luminosity at the LHC.

   hep-phPRD(2018)·8 citations
4. 04*

   Standard Model EFT and Extended Scalar Sectors

   Sally Dawson🇺🇸 · Christopher W. Murphy🇺🇸

   One of the simplest extensions of the Standard Model is the inclusion of an additional scalar multiplet, and we consider scalars in the $SU(2{)}_L$ singlet, triplet, and quartet representations. We examine models with heavy neutral scalars, $m_H\sim 1-2$ TeV, and the matching of the UV complete theories to the low energy effective field theory. We demonstrate the agreement of the kinematic distributions obtained in the singlet models for the gluon fusion of a Higgs pair with the predictions of the effective field theory. The restrictions on the extended scalar sectors due to unitarity and precision electroweak measurements are summarized and lead to highly restricted regions of viable parameter space for the triplet and quartet models.

   hep-phPRD(2017)·79 citations
5. 05*

   Theoretical Perspective on Quarkonia from SPS via RHIC to LHC

   Ralf Rapp🇺🇸 · Xiaojian Du🇺🇸

   The objective of this paper is to assess the current theoretical understanding of the extensive set of quarkonium observables (for both charmonia and bottomonia) that have been attained in ultrarelativistic heavy-ion collisions over two orders of magnitude in center-of-mass energy. We briefly lay out and compare the currently employed theoretical frameworks and their underlying transport coefficients, and then analyze excitation functions of quarkonium yields to characterize the nature of the varying production mechanisms. We argue that an overall coherent picture of suppression and regeneration mechanisms emerges which enables to deduce insights on the properties of the in-medium QCD force from SPS via RHIC to LHC, and forms a basis for future quantitative studies.

   hep-phnucl-exnucl-thNPA(2017)·36 citations
6. 06*

   Heavy quark form factors in the large ${\beta }_0$ limit

   A. G. Grozin🇷🇺

   Heavy quark form factors are calculated at ${\beta }_0{\alpha }_s\sim 1$ to all orders in ${\alpha }_s$ at the first order in $1/{\beta }_0$. The $n_f^2{\alpha }_s^3$ terms in the recent results [arXiv:1611.07535] for the vector form factors are confirmed, and $n_f^{L-1}{\alpha }_s^L$ terms for higher $L$ are predicted.

   hep-phEPJC(2017)·11 citations
7. 07*

   CSM analyses of $e^{+}{e}^{-}\to t\bar{t}H,t\bar{t}Z,t\bar{b}W$

   Fernand M. Renard🇫🇷

   We study the modifications of the amplitudes and cross sections of several processes, especially $e^{+}{e}^{-}\to t\bar{t}H,t\bar{t}Z,t\bar{b}W$, generated by Higgs boson and top quark compositeness, in particular within the CSM concept. We illustrate the observable differences that may appear between various, CSM conserving or CSM violating, compositeness possibilities.

   hep-ph2 citations
8. 08*

   Statistical Methods for the Neutrino Mass Hierarchy

   Emilio Ciuffoli🇨🇳

   In the next decade several experiments will attempt to determine the neutrino mass hierarchy, i.e. the sign of $\Delta m_{31}^2$. In the last years it was noticed that the two hierarchies are disjoint hypotheses and, for this reason, Wilks' theorem cannot be applied: this means that $\Delta {\chi }^2={\chi }_{IH}^2-{\chi }_{NH}^2$ does not follow a one-degree-of-freedom chi-square distribution. It was proven that, under certain assumptions, it follows instead a Gaussian distribution with $\sigma =2\sqrt{\mu }$. I will present several possible definition of sensitivity and review the approaches proposed in the literature, both within the Bayesian and the frequentist framework, examining advantages and disadvantages and discussing how they should be modified if the conditions for Gaussianity are not fulfilled. I will also discuss the possibility of introducing a new pull parameter in order to avoid the issue related to the non-nested hypotheses and the differences between marginalization and minimization, showing under which conditions the two procedures yield the same $\Delta {\chi }^2$.

   hep-ph4 citations
9. 09*

   Photon-jet correlations in Deep-Inelastic Scattering

   P. Aurenche🇫🇷 · M. Fontannaz🇫🇷

   The reaction e + p ---> photon + jet + X is studied in QCD at the next-to-leading order. Previous studies on inclusive distributions showed a good agreement with ZEUS data. To obtain a finer understanding of the dynamics of the reaction, several correlation functions are evaluated for ZEUS kinematics.

   hep-phEPJC(2017)·4 citations
10. 10*

    Natural Supersymmetry from the Yukawa Deflect Mediations

    Tai-ran Liang🇨🇳 · Bin Zhu🇨🇳 · Ran Ding🇨🇳 · Tianjun Li🇨🇳

    The natural supersymmetry (SUSY) requires light stop quarks, light sbottom quark, and gluino to be around one TeV or lighter. The first generation squarks can be effectively large which does not introduce any hierarchy problem in order to escape the constraints from LHC. In this paper we consider a Yukawa deflect medation to realize the effective natural supersymmetry where the interaction between squarks and messenger are made natural under certain Frogget-Nelson $U(1{)}_X$ charge. The first generation squarks obtain large and postive contribution from the yukawa deflect mediation. The corresponding phenomenology as well as sparticle spectrum are discussed in detail.

    hep-phAdv.High Energy Phys.(2017)·3 citations
11. 11*

    Universal scaling of strange particle $p_{\mathrm{T}}$ spectra in pp collisions

    Liwen Yang🇨🇳 · Yanyun Wang🇨🇳 · Wenhui Hao🇨🇳 · Na Liu🇨🇳 · Xiaoling Du🇨🇳 · Wenchao Zhang🇨🇳

    As a complementary study to that performed on the transverse momentum ($p_{\mathrm{T}}$) spectra of charged pions, kaons and protons in proton-proton (pp) collisions at LHC energies 0.9, 2.76 and 7 TeV, we present a scaling behaviour in the $p_{\mathrm{T}}$ spectra of strange particles ($K_S^0$, $\mathrm{\Lambda }$, $\mathrm{\Xi }$ and $\varphi$) at these three energies. This scaling behaviour is exhibited when the spectra are expressed in a suitable scaling variable $z=p_{\mathrm{T}}/K$, where the scaling parameter $K$ is determined by the quality factor method and increases with the center of mass energy ($\sqrt{s}$). The rates at which $K$ increases with $\ln \sqrt{s}$ for these strange particles are found to be identical within errors. In the framework of the colour string percolation model, we argue that these strange particles are produced through the decay of clusters that are formed by the colour strings overlapping. We observe that the strange mesons and baryons are produced from clusters with different size distributions, while the strange mesons (baryons) $K_S^0$ and $\varphi$ ($\mathrm{\Lambda }$ and $\mathrm{\Xi }$) originate from clusters with the same size distributions. The cluster's size distributions for strange mesons are more dispersed than those for strange baryons. The scaling behaviour of the $p_{\mathrm{T}}$ spectra for these strange particles can be explained by the colour string percolation model in a quantitative way.

    hep-phEPJA(2018)·5 citations
12. 12*

    Anomaly-free local horizontal symmetry and anomaly-full rare B-decays

    Rodrigo Alonso🇨🇭 · Peter Cox🇯🇵 · Chengcheng Han🇯🇵 · Tsutomu T. Yanagida🇯🇵

    The largest global symmetry that can be made local in the Standard Model + 3${\nu }_R$ while being compatible with Pati-Salam unification is $SU(3{)}_H\times U(1{)}_{B-L}$. The gauge bosons of this theory would induce flavour effects involving both quarks and leptons, and are a potential candidate to explain the recent reports of lepton universality violation in rare B meson decays. In this letter we characterise this type of models and show how they can accommodate the data and naturally be within reach of direct searches.

    hep-phPRD(2017)·73 citations
13. 13*

    Implications of the $R_K$ and $R_{K^{\ast }}$ anomalies

    Wei Wang🇨🇳 · Shuai Zhao🇨🇳

    We discuss the implications of the recently reported $R_K$ and $R_{K^{\ast }}$ anomalies, the lepton flavor non-universality in the $B\to K{\ell }^{+}{\ell }^{-}$ and $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$. Using two sets of hadronic inputs of form factors, we perform a fit of the new physics to the $R_K$ and $R_{K^{\ast }}$ data, and significant new physics contributions are found. We suggest to study the lepton flavor universality in a number of related rare $B,B_s,B_c$ and ${\Lambda }_b$ decay channels, and in particular we give the predictions for the $\mu$-to-$e$ ratios of decay widths with different polarizations of the final state particles, and of the $b\to d{\ell }^{+}{\ell }^{-}$ processes which are presumably more sensitive to the structure of the underlying new physics. With the new physics contributions embedded in Wilson coefficients, we present theoretical predictions for lepton flavor non-universality in these processes.

    hep-phhep-exCPC(2018)·26 citations
14. 14*

    LHC as an Axion Factory: Probing an Axion Explanation for $(g-2{)}_{\mu }$ with Exotic Higgs Decays

    Martin Bauer🇩🇪 · Matthias Neubert🇩🇪 · Andrea Thamm🇩🇪

    We argue that a large region of so far unconstrained parameter space for axion-like particles (ALPs), where their couplings to the Standard Model are of order $(0.01-1)\text{mbox}{TeV}^{-1}$, can be explored by searches for the exotic Higgs decays $h\to Za$ and $h\to aa$ in Run-2 of the LHC. Almost the complete region in which ALPs can explain the anomalous magnetic moment of the muon can be probed by searches for these decays with subsequent decay $a\to \gamma \gamma$, even if the relevant couplings are loop suppressed and the $a\to \gamma \gamma$ branching ratio is less than~1.

    hep-phPRL(2017)·107 citations
15. 15*

    Higgs-differential cross section at NNLO in dimensional regularisation

    Falko Dulat🇺🇸 · Simone Lionetti🇨🇭 · Bernhard Mistlberger🇨🇭 · Andrea Pelloni🇨🇭 · Caterina Specchia🇨🇭

    We present an analytic computation of the Higgs production cross section in the gluon fusion channel, which is differential in the components of the Higgs momentum and inclusive in the associated partonic radiation through NNLO in perturbative QCD. Our computation includes the necessary higher order terms in the dimensional regulator beyond the finite part that are required for renormalisation and collinear factorisation at N${}^3$LO. We outline in detail the computational methods which we employ. We present numerical predictions for realistic final state observables, specifically distributions for the decay products of the Higgs boson in the $\gamma \gamma$ decay channel.

    hep-phJHEP(2017)·27 citations
16. 16*

    How Much Information is in a Jet?

    Kaustuv Datta🇺🇸 · Andrew Larkoski🇺🇸

    Machine learning techniques are increasingly being applied toward data analyses at the Large Hadron Collider, especially with applications for discrimination of jets with different originating particles. Previous studies of the power of machine learning to jet physics has typically employed image recognition, natural language processing, or other algorithms that have been extensively developed in computer science. While these studies have demonstrated impressive discrimination power, often exceeding that of widely-used observables, they have been formulated in a non-constructive manner and it is not clear what additional information the machines are learning. In this paper, we study machine learning for jet physics constructively, expressing all of the information in a jet onto sets of observables that completely and minimally span N-body phase space. For concreteness, we study the application of machine learning for discrimination of boosted, hadronic decays of Z bosons from jets initiated by QCD processes. Our results demonstrate that the information in a jet that is useful for discrimination power of QCD jets from Z bosons is saturated by only considering observables that are sensitive to 4-body (8 dimensional) phase space.

    hep-phhep-exJHEP(2017)·116 citations
17. 17*

    WIMPs with GUTs: Dark Matter Coannihilation with a Lighter Species

    Asher Berlin🇺🇸

    We propose a new thermal freeze-out mechanism for ultra-heavy dark matter. Dark matter coannihilates with a lighter unstable species, leading to an annihilation rate that is exponentially enhanced relative to standard WIMPs. This scenario destabilizes any potential dark matter candidate. In order to remain consistent with astrophysical observations, our proposal necessitates very long-lived states, motivating striking phenomenology associated with the late decays of ultra-heavy dark matter, potentially as massive as the scale of grand unified theories, $M_{\text{GUT}}\sim 10^{16}$ GeV.

    hep-phastro-ph.COPRL(2017)·31 citations
18. 18*

    Interference in the $gg\to h\to \gamma \gamma$ On-Shell Rate and the Higgs Boson Total Width

    John Campbell🇺🇸 · Marcela Carena🇺🇸 · Roni Harnik🇺🇸 · Zhen Liu🇺🇸

    We consider interference between the Higgs signal and QCD background in $gg\to h\to \gamma \gamma$ and its effect on the on-shell Higgs rate. The existence of sizable strong phases leads to destructive interference of about 2% of the on-shell cross section in the Standard Model. This effect can be enhanced by beyond the standard model physics. In particular, since it scales differently from the usual rates, the presence of interference allows indirect limits to be placed on the Higgs width in a novel way, using on-shell rate measurements. Our study motivates further QCD calculations to reduce uncertainties. We discuss potential width-sensitive observables, both using total and differential rates and find that the HL-LHC can potentially indirectly probe widths of order tens of MeV.

    hep-phhep-exPRL(2017)·54 citations
19. 19*

    Soft Functions for Generic Jet Algorithms and Observables at Hadron Colliders

    Daniele Bertolini🇺🇸 · Daniel Kolodrubetz🇺🇸 · Duff Neill🇺🇸 · Piotr Pietrulewicz🇩🇪 · Iain W. Stewart🇺🇸 · Frank J. Tackmann🇩🇪 · Wouter J. Waalewijn🇳🇱

    We introduce a method to compute one-loop soft functions for exclusive $N$-jet processes at hadron colliders, allowing for different definitions of the algorithm that determines the jet regions and of the measurements in those regions. In particular, we generalize the $N$-jettiness hemisphere decomposition of [Jouttenus 2011] in a manner that separates the dependence on the jet boundary from the observables measured inside the jet and beam regions. Results are given for several factorizable jet definitions, including anti-$k_T$, XCone, and other geometric partitionings. We calculate explicitly the soft functions for angularity measurements, including jet mass and jet broadening, in $pp\to L+1$ jet and explore the differences for various jet vetoes and algorithms. This includes a consistent treatment of rapidity divergences when applicable. We also compute analytic results for these soft functions in an expansion for a small jet radius $R$. We find that the small-$R$ results, including corrections up to $\mathcal{O}(R^2)$, accurately capture the full behavior over a large range of $R$.

    hep-phJHEP(2017)·19 citations
20. 20*

    Reply to "Comment on `Finding the $0^{--}$ Glueball'" [arXiv:1702.06634] and comment on `Is the exotic $0^{--}$ glueball a pure gluon state?' [arXiv:1611.08698]

    Cong-Feng Qiao🇨🇳 · Liang Tang🇨🇳

    A Reply to "Comment on `Finding the $0^{--}$ Glueball' " [arXiv:1702.06634] and comment on `Is the exotic $0^{--}$ glueball a pure gluon state?' [arXiv:1611.08698]

    hep-ph2 citations
21. 21*

    Probing the spacetime evolution of heavy ion collisions with photons and dileptons

    Jean-François Paquet🇺🇸

    Photons and dileptons are emitted throughout the evolution of the deconfined nuclear medium produced in heavy ion collisions. As such they can provide valuable information about the different phases of the medium, and complement hadronic measurements and other observables. In this work, recent developments related to electromagnetic emissions at early time, in the cross-over region, and at late times are reviewed. The spacetime description of the nuclear medium from a hydrodynamic model of heavy ion collisions is used to provide context and guide the discussion.

    ↳ nucl-thhep-phNPA(2017)·23 citations
22. 22*

    Equation of state of a quark-meson mixture in the improved-PNJL model at finite chemical potential

    Juan M. Torres-Rincon🇩🇪 · Joerg Aichelin🇫🇷

    We study the equation of state of QCD using an improved version of the three-flavor Polyakov-Nambu-Jona-Lasinio model beyond the mean-field approximation. It incorporates the effects of unquenched quarks into the Polyakov-loop effective potential, as well as mesonic contributions to the grand-canonical potential. We study in full detail the calculation of the thermodynamical potential in this approach and compare the resulting pressure and entropy density with the most-recent lattice-QCD calculations at zero baryochemical potential. Finally, we present some exploratory results at finite chemical potential which include the phase diagram of the model, the quark and meson masses, and finally, the thermodynamical pressure.

    ↳ nucl-thhep-phPRC(2017)·35 citations
23. 23*

    Diagrammatic Hopf algebra of cut Feynman integrals: the one-loop case

    Samuel Abreu🇩🇪 · Ruth Britto🇮🇪 · Claude Duhr🇨🇭 · Einan Gardi🇬🇧

    We construct a diagrammatic coaction acting on one-loop Feynman graphs and their cuts. The graphs are naturally identified with the corresponding (cut) Feynman integrals in dimensional regularization, whose coefficients of the Laurent expansion in the dimensional regulator are multiple polylogarithms (MPLs). Our main result is the conjecture that this diagrammatic coaction reproduces the combinatorics of the coaction on MPLs order by order in the Laurent expansion. We show that our conjecture holds in a broad range of nontrivial one-loop integrals. We then explore its consequences for the study of discontinuities of Feynman integrals, and the differential equations that they satisfy. In particular, using the diagrammatic coaction along with information from cuts, we explicitly derive differential equations for any one-loop Feynman integral. We also explain how to construct the symbol of any one-loop Feynman integral recursively. Finally, we show that our diagrammatic coaction follows, in the special case of one-loop integrals, from a more general coaction proposed recently, which is constructed by pairing master integrands with corresponding master contours.

    ↳ hep-thhep-phJHEP(2017)·97 citations
24. 24*

    What Can Gamma-rays from Space tell us About the Madala Hypothesis?

    Geoff Beck🇿🇦 · Sergio Colafrancesco🇿🇦

    The recent Madala hypothesis, a conjecture that seeks to explain anomalies within Large Hadron Collider (LHC) data (particularly in the transverse momentum of the Higgs boson), is interesting for more than just a statistical hint at unknown and unpredicted physics. This is because the model itself contains additional new particles that may serve as Dark Matter (DM) candidates. These particles interact with the Standard Model via a scalar mediator boson $S$. More interesting still, the conjectured mass range for the DM candidate ($65$ - $100$ GeV) lies within the region of models viable to try explain the recent Galactic Centre (GC) gamma-ray excess seen by Fermi Large Area Telescope (Fermi-LAT) and the High Energy Stereoscopic System (HESS). Therefore, assuming $S$ decays promptly, it should be possible to check what constraints are imposed upon the effective DM annihilation cross-section in the Madala scenario by hunting signatures of $S$ decay that follows DM annihilation within dense astrophysical structures. In order to make use of existing data, we use the Reticulum II dwarf galaxy and the galactic centre gamma-ray excess data sets from Fermi-LAT, and compare these to the consequences of various decay paths for $S$ in the aforementioned environments. We find that, based on this existing data, we can limit $\tau$ lepton, quark, direct gamma-ray, and weak boson channels to levels below the canonical relic cross-section. This allows us to set new limits on the branching ratios of $S$ decay, which can rule out a Higgs-like decay branching for $S$, in the case where the Madala DM candidate is assumed to comprise all DM.

    ↳ astro-ph.COhep-phJ.Phys.Conf.Ser.(2017)·3 citations
25. 25*

    Roadmap for the international, accelerator-based neutrino programme

    J. Cao🇨🇳 · A. de Gouvea🇺🇸 · D. Duchesneau🇫🇷 · S. Geer🇺🇸 · R. Gomes🇧🇷 · S.B. Kim🇰🇷 · T. Kobayashi🇯🇵 · K.R. Long🇬🇧 · M. Maltoni🇪🇸 · M. Mezzetto🇮🇹 · N. Mondal🇮🇳 · M. Shiozawa🇯🇵 and 4 other authors

    In line with its terms of reference the ICFA Neutrino Panel has developed a roadmapfor the international, accelerator-based neutrino programme. A "roadmap discussion document" was presented in May 2016 taking into account the peer-group-consultation described in the Panel's initial report. The "roadmap discussion document" was used to solicit feedback from the neutrino community---and more broadly, the particle- and astroparticle-physics communities---and the various stakeholders in the programme. The roadmap, the conclusions and recommendations presented in this document take into account the comments received following the publication of the roadmap discussion document. With its roadmap the Panel documents the approved objectives and milestones of the experiments that are presently in operation or under construction. Approval, construction and exploitation milestones are presented for experiments that are being considered for approval. The timetable proposed by the proponents is presented for experiments that are not yet being considered formally for approval. Based on this information, the evolution of the precision with which the critical parameters governinger the neutrino are known has been evaluated. Branch or decision points have been identified based on the anticipated evolution in precision. The branch or decision points have in turn been used to identify desirable timelines for the neutrino-nucleus cross section and hadro-production measurements that are required to maximise the integrated scientific output of the programme. The branch points have also been used to identify the timeline for the R&D required to take the programme beyond the horizon of the next generation of experiments. The theory and phenomenology programme, including nuclear theory, required to ensure that maximum benefit is derived from the experimental programme is also discussed.

    ↳ hep-exhep-phphysics.ins-det11 citations
26. 26*

    Probing dark matter annihilation in the Galaxy with antiprotons and gamma rays

    Alessandro Cuoco🇩🇪 · Jan Heisig🇩🇪 · Michael Korsmeier🇩🇪 · Michael Krämer🇩🇪

    A possible hint of dark matter annihilation has been found in Cuoco, Korsmeier and Krämer (2017) from an analysis of recent cosmic-ray antiproton data from AMS-02 and taking into account cosmic-ray propagation uncertainties by fitting at the same time dark matter and propagation parameters. Here, we extend this analysis to a wider class of annihilation channels. We find consistent hints of a dark matter signal with an annihilation cross-section close to the thermal value and with masses in range between 40 and 130 GeV depending on the annihilation channel. Furthermore, we investigate in how far the possible signal is compatible with the Galactic center gamma-ray excess and recent observation of dwarf satellite galaxies by performing a joint global fit including uncertainties in the dark matter density profile. As an example, we interpret our results in the framework of the Higgs portal model.

    ↳ astro-ph.HEhep-phJCAP(2017)·87 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.