Fri·Jan 10, 2020Friday·January 10, 2020

1. 01*

   LHC dijet angular distributions as a probe for the dimension-six triple gluon vertex

   Reza Goldouzian🇺🇸 · Michael D. Hildreth🇺🇸

   In the absence of a concrete discovery of new physics at the LHC, global analyses of the standard model effective field theory (SMEFT) are important to find and describe the impact of new physics beyond the energy reach of the LHC. Among the SMEFT operators that can be constrained via various measurements, the dimension six triple gluon operator involves neither the Higgs boson nor the top quark, yet its variation can have measurable effects on top and Higgs production. Without independent constraints on its impact, the sensitivity of measurements in the top and Higgs sectors to new physics is reduced. We show that the dijet angular distribution is a powerful observable for probing the triple gluon operator. We set the most stringent limit on the triple gluon effective coupling by reinterpreting the results of a search for new phenomena in dijet events using 35.9 fb${}^{-1}$ of pp collision data collected at $\sqrt{s}$ = 13 TeV performed by the CMS collaboration. The obtained limit on the strength of the triple gluon operator is far below the sensitivity of that which can be derived from top quark and Higgs measurements and thus this operator can be neglected in global SMEFT analyses.

   hep-phPLB(2020)·28 citations
2. 02*

   High-precision four-loop mass and wave function renormalization in QED

   Stefano Laporta🇮🇹

   The 4-loop QED mass and wave function renormalization constants $Z_2$ and $Z_m$ have been evaluated in the on-shell subtraction scheme with 1100 digits of precision. We also worked out the coefficients of the five color structures of the QCD renormalization constants $Z_2^{OS}$ and $Z_m^{OS}$ which can obtained from QED-like diagrams. The results agree with lower precision results available in the literature. Analytical fits were also obtained for all these quantities.

   hep-phPLB(2020)·7 citations
3. 03*

   Vector-like Quark Interpretation for the CKM Unitarity Violation, Excess in Higgs Signal Strength, and Bottom Quark Forward-Backward Asymmetry

   Kingman Cheung🇹🇼 · Wai-Yee Keung🇺🇸 · Chih-Ting Lu🇰🇷 · Po-Yan Tseng🇰🇷

   Due to a recent more precise evaluation of $V_{ud}$ and $V_{us}$, the unitarity condition of the first row in the Cabibbo-Kobayashi-Maskawa (CKM) matrix: $|V_{ud}{|}^2+|V_{us}{|}^2+|V_{ub}{|}^2=0.99798\pm 0.00038$ now stands at a deviation more than $4\sigma$ from unity. Furthermore, a mild excess in the overall Higgs signal strength appears at about $2\sigma$ above the standard model (SM) prediction, as well as the long-lasting discrepancy in the forward-backward asymmetry ${\mathcal{A}}_{\mathrm{FB}}^b$ in $Z\to b\bar{b}$ at LEP. Motivated from the above three anomalies we investigate an extension of the SM with vector-like quarks (VLQs) associated with the down-quark sector, with the goal of alleviating the tension among these datasets. We perform global fits of the model under the constraints coming from the unitarity condition of the first row of the CKM matrix, the $Z$-pole observables ${\mathcal{A}}_{\mathrm{FB}}^b$, $R_b$ and ${\Gamma }_{\mathrm{had}}$, Electro-Weak precision observables $\Delta S$ and $\Delta T$, $B$-meson observables $B_d^0$-${\overline{B}}_d^0$ mixing, $B^{+}\to {\pi }^{+}{\ell }^{+}{\ell }^{-}$ and $B^0\to {\mu }^{+}{\mu }^{-}$, and direct searches for VLQs at the Large Hadron Collider (LHC). Our results suggest that adding VLQs to the SM provides better agreement than the SM.

   hep-phJHEP(2020)·49 citations
4. 04*

   QCD phase diagram at finite isospin chemical potential and temperature in an IR-improved soft-wall AdS/QCD model

   Xuanmin Cao🇨🇳 · Hui Liu🇨🇳 · Danning Li🇨🇳 · Guanning Ou🇨🇳

   We study the phase transition between pion condensed phase and normal phase, as well as chiral phase transition in a two flavor(${\mathcal{N}}_f=2$) IR- improved soft-wall AdS/QCD model at finite isospin chemical potential ${\mu }_I$ and temperature $T$. By self-consistently solving the equations of motion, we obtain the phase diagram in the plane of ${\mu }_I$ and $T$. The pion condensation appears together with a massless Nambu-Goldstone boson $m_{{\pi }_1}(T_c,{\mu }_I^c)=0$, which is very likely to be a second-order phase transition with mean-field critical exponents in small ${\mu }_I$ region. When $T=0$, the critical isospin chemical potential approximates to vacuum pion mass ${\mu }_I^c\approx m_0$. The pion condensed phase exists in an arched area and the boundary of the chiral crossover intersects the pion condensed phase at a tri-critical point. Qualitatively, the results are in good agreement with previous studies from Lattice simulations and model calculations.

   hep-phhep-thCPC(2020)·19 citations
5. 05*

   Observed ${\Omega }_b$ spectrum and meson-baryon molecular states

   Wei-Hong Liang🇨🇳 · E. Oset🇪🇸

   We observe that four peaks seen in the high energy part of the ${\Omega }_b$ spectrum of the recent LHCb experiment are in remarkable agreement with predictions made for molecular ${\Omega }_b$ states stemming from the meson-baryon interaction, with an approach that applied to the ${\Omega }_c$ states gave rise to three states in good agreement with experiment in masses and widths. While the statistical significance of the peaks prevents us from claims of states at the present time, the agreement found should be an incentive to look at this experiment with increased statistics to give an answer to this suggestive idea.

   hep-phhep-exnucl-thPRD(2020)·23 citations
6. 06*

   Tetrahedral Symmetry A${}_4$ in Anti-SU(5) GUT

   Paul H. Frampton🇮🇹 · Jihn E. Kim🇰🇷 · Se-Jin Kim · Soonkeon Nam🇰🇷

   We construct a flavor model in an anti-SU(5) GUT with a tetrahedral symmetry $A_4$. We choose a basis where $Q_{textem}=-\frac{1}{3}$ quarks and charged leptons are already mass eigenstates. This choice is possible from the $A_4$ symmetry. Then, matter representation ${\overline{10}}_{-1}^{\mathrm{matter}}$ contains both a quark doublet and a heavy neutrino $N$, which enables us to use the $A_4$ symmetry to both $Q_{textem}=+\frac{2}{3}$ quark masses and neutrino masses (through the see-saw via $N$). This is made possible because the anti-SU(5) breaking is achieved by the Higgs fields transforming as anti-symmetric representations of SU(5), ${\overline{10}}_{-1}^H\oplus 10_{+1}^H$, reducing the rank-5 anti-SU(5) group down to the rank-4 standard model group \smg. For possible mass matrices, the $A_4$ symmetry predictions on mass matrices at field theory level are derived. Finally, an illustration from string compactification is presented.

   hep-phhep-thPRD(2020)·7 citations
7. 07*

   Analysis of the ${\Omega }_b(6316)$, ${\Omega }_b(6330)$, ${\Omega }_b(6340)$ and ${\Omega }_b(6350)$ with QCD sum rules

   Zhi-Gang Wang🇨🇳

   In this article, we introduce an explicit P-wave to construct three-quark currents to study the P-wave ${\Omega }_b$ states with the full QCD sum rules. The predicted masses have a hierarchy if the same parameters are chosen and favor assigning the ${\Omega }_b(6316)$, ${\Omega }_b(6330)$, ${\Omega }_b(6340)$ and ${\Omega }_b(6350)$ to be the P-wave ${\Omega }_b$ states with the $J^P={\frac{3}{2}}^{-}$, ${\frac{1}{2}}^{-}$, ${\frac{5}{2}}^{-}$ and ${\frac{3}{2}}^{-}$, respectively.

   hep-phInt.J.Mod.Phys.A(2020)·32 citations
8. 08*

   Recently observed $P_c$ as molecular states and possible mixture of $P_c(4457)$

   Hao Xu🇨🇳 · Qiang Li🇨🇳 · Chao-Hsi Chang🇨🇳 · Guo-Li Wang🇨🇳

   Recently observed spectrum of $P_c$ states exhibits a strong link to ${\Sigma }_c{\bar{D}}^{(\ast )}$ thresholds. In spite of successful molecular interpretations, we still push forward to wonder whether there exist finer structures. Utilizing the effecitve lagrangians respecting heavy quark symmetry and chiral symmetry, as well as instantaneous Bethe-Salpeter equations, we investigate the ${\Sigma }_c{\bar{D}}^{(\ast )}$ interactions and three $P_c$ states. We confirm that $P_c(4312)$ and $P_c(4440)$ are good candidates of ${\Sigma }_c\bar{D}$ and ${\Sigma }_c{\bar{D}}^{\ast }$ molecules with spin-$\frac{1}{2}$, respectively. Unlike other molecular calculations, our results indicate $P_c(4457)$ signal might be a mixture of spin-$\frac{3}{2}$ and spin-$\frac{1}{2}$ ${\Sigma }_c{\bar{D}}^{\ast }$ molecules, where the latter one appears to be an excitation of $P_c(4440)$. Therefore we conclude that, confronting three LHCb $P_c$ signals, there may exist not three, but four molecular states.

   hep-phPRD(2020)·44 citations
9. 09*

   Exact quark-mass dependence of the Higgs-gluon form factor at three loops in QCD

   M. Czakon🇩🇪 · M. Niggetiedt🇩🇪

   We determine the three-loop form factor parameterising the amplitude for the production of an off-shell Higgs boson in gluon fusion in QCD with a single massive quark. The result is obtained via a numerical solution of a system of differential equation for the occurring master integrals. The solution is also used to determine the high-energy and threshold expansions of the form factor. Our findings may be used for the evaluation of virtual corrections generated by top-quark and b-quark loops in Higgs boson hadroproduction cross sections at next-to-next-to-leading order.

   hep-phJHEP(2020)·69 citations
10. 10*

    Neutrino physics outlook

    José W. F. Valle🇪🇸

    Here I identify some of the opportunities in particle physics associated to the lepton sector, according to their perceived significance, and taking into account the current state-of-the-art.

    hep-phhep-exPoS(2020)·2 citations
11. 11*

    Associated top quark pair production with a heavy boson: differential cross sections at NLO+NNLL accuracy

    Anna Kulesza🇩🇪 · Leszek Motyka🇵🇱 · Daniel Schwartländer🇩🇪 · Tomasz Stebel🇵🇱 · Vincent Theeuwes🇩🇪

    We present theoretical predictions for selected differential cross sections for the process $pp\to t\bar{t}B$ at the LHC, where $B$ can be a Higgs ($H$), a $Z$ or a $W$ boson. The predictions are calculated in the direct QCD framework up to the next-to-next-leading logarithmic (NNLL) accuracy and matched to the complete NLO results including QCD and electroweak effects. Additionally, results for the total cross sections are provided. The calculations deliver a significant improvement of the theoretical predictions, especially for the $t\bar{t}H$ and the $t\bar{t}Z$ production. In these cases, predictions for both the total and differential cross sections are remarkably stable with respect to the central scale choice and carry a substantially reduced scale uncertainty in comparison with the complete NLO predictions.

    hep-phEPJC(2020)·112 citations
12. 12*

    Electric charge assignment in quantum field theories

    E. Castillo-Ruiz🇵🇪 · V. Pleitez🇧🇷 · O. P. Ravinez🇵🇪

    In Field theories with simple or semi-simple unitary, local or global symmetries, the electric charge is related to a global one. This is the case also in electroweak gauge theories even before the spontaneous symmetry breaking (SSB), where these quantities are defined in order to expand the Lagrangian respecting the conservation laws after the breaking. So, the electric charge assignment within a given multiplet is done (in units of jej) considering only global symmetries, even though in general, the electric charge operator is a linear combination of the diagonal generators of the non-Abelian symmetry plus some Abelian factor. In this work we show how this operator can be systematically constructed from any representation in the Standard Model and some of its extensions as the 3-3-1, left-right symmetric and grand unified models.

    hep-phhep-th2 citations
13. 13*

    Non-monotonic energy dependence of net-proton number fluctuations

    STAR Collaboration: J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D. M. Anderson · A. Aparin · E. C. Aschenauer · M. U. Ashraf and 346 other authors

    Non-monotonic variation with collision energy ($\sqrt{s_{\mathrm{NN}}}$) of the moments of the net-baryon number distribution in heavy-ion collisions, related to the correlation length and the susceptibilities of the system, is suggested as a signature for the Quantum Chromodynamics (QCD) critical point. We report the first evidence of a non-monotonic variation in kurtosis times variance of the net-proton number (proxy for net-baryon number) distribution as a function of \rootsnn with 3.1$\sigma$ significance, for head-on (central) gold-on-gold (Au+Au) collisions measured using the STAR detector at RHIC. Data in non-central Au+Au collisions and models of heavy-ion collisions without a critical point show a monotonic variation as a function of $\sqrt{s_{\mathrm{NN}}}$.

    ↳ nucl-exhep-exhep-phnucl-thPRL(2021)·377 citations
14. 14*

    Emergence of Quark-Gluon Plasma Phenomena

    Jan Fiete Grosse-Oetringhaus🇨🇭

    The discovery of QGP phenomena in small collision systems like pp and p-Pb collisions have challenged the basic paradigms of heavy-ion and high-energy physics. These proceedings give a brief overview of the key findings and their implications, as well as today's experimental and theoretical situation. An outlook of future measurement is made.

    ↳ nucl-exhep-exhep-phPoS(2020)·3 citations
15. 15*

    Defiducialization: Providing Experimental Measurements for Accurate Fixed-Order Predictions

    Alexander Glazov🇩🇪

    An experimental procedure is proposed to perform measurements of differential cross sections which can be compared to fixed-order QCD predictions with improved accuracy. The procedure can be applied to the Drell-Yan cross-section measurements which are differential in the boson transverse momentum. An example analysis is performed using the ATLAS measurement of the $Z$-boson production cross section at center-of-mass energy of $8$ TeV. The resulting full phase space measurement of the cross section differential in the boson rapidity is compared to theoretical predictions computed with next-to-next-to leading-order accuracy in QCD.

    ↳ hep-exhep-phEPJC(2020)·7 citations
16. 16*

    Examining the secondary product origin of cosmic ray positrons with the latest AMS-02 data

    Zhi-Qiu Huang🇨🇳 · Ruo-Yu Liu🇨🇳 · Jagdish C. Joshi🇨🇳 · Xiang-Yu Wang🇨🇳

    Measurements of cosmic-ray (CR) positron fraction by PAMELA and other experiments have found an excess above 10 GeV relative to the standard predictions for secondary production in the interstellar medium (ISM). Although the excess has been mostly suggested to arise from some primary sources of positrons (such as pulsars and or annihilating dark matter particles), the almost constant flux ratio of $e^{+}/\bar{p}$ argues for an alternative possibility that the excess positrons and antiprotons up to the highest energies are secondary products generated in hadronic interactions. Recently, Yang \& Aharonian (2019) revisit this possibility by assuming the presence of an additional population of CR nuclei sources. Here we examine this secondary product scenario using the \texttt{DRAGON} code, where the radiative loss of positrons is taken into account consistently. We confirm that the CR proton spectrum and the antiproton data can be explained by assuming the presence of an additional population of CR sources. However, the corresponding positron spectrum deviates from the measured data significantly above 100 GeV due to the strong radiative cooling. This suggests that, although hadronic interactions can explain the antiproton data, the corresponding secondary positron flux is still not enough to account for the AMS data. Hence contribution from some primary positron sources, such as pulsars or dark matter, is non-negligible.

    ↳ astro-ph.HEhep-phApJ(2020)·5 citations
17. 17*

    Killing Spinor in Linearly Confining Supergravity

    Girma Hailu🇺🇸

    The killing spinor of a linearly confining supergravity background previously proposed and argued to produce features of pure N=1 SU(N) gauge theory in four dimensions is constructed directly using the supersymmetry variations of the gravitino and the dilatino.

    ↳ hep-thhep-ph0 citations
18. 18*

    Merger rate distribution of primordial black hole binaries with electric charges

    Lang Liu🇨🇳 · Zong-Kuan Guo🇨🇳 · Rong-Gen Cai🇨🇳 · Sang Pyo Kim🇨🇳

    We consider gravitational radiation and electromagnetic radiation from point mass binary with electric charges in a Keplerian orbit, and calculate the merger rate distribution of primordial black hole binaries with charges and a general mass function by taking into account gravitational torque and electromagnetic torque by the nearest primordial black hole. We apply the formalism to the extremal charged case and find that $\alpha =-(m_i+m_j{)}^2{\partial }^2\ln \mathcal{R}(m_i,m_j)/\partial m_i\partial m_j=12/11$, which is independent of the mass function.

    ↳ astro-ph.COgr-qchep-phPRD(2020)·70 citations
19. 19*

    WIMP Dark Matter at the International Linear Collider

    Moritz Habermehl🇩🇪 · Mikael Berggren🇩🇪 · Jenny List🇩🇪

    In this study, the sensitivity of future lepton colliders to WIMP dark matter is evaluated assuming WIMP pair production accompanied by a photon from initial state radiation, through which the process can be identified. A full detector simulation for the International Large Detector (ILD) concept at the International Linear Collider (ILC) is performed for a \com energy of 500\,GeV. Energy scales of up to $3$\,TeV can be tested for different effective operators for WIMP masses almost up to half the \com energy. The sensitivity benefits from the polarised beams, which can reduce the main SM background from neutrino pair production substantially. In addition, systematic uncertainties are shown to be significantly reduced by combining data with several different polarisation configurations. In comparison to a previous study, the reconstruction of the forward detectors has been improved and the systematic uncertainties are fully treated. The results are also extrapolated to other \com energies, luminosities and beam polarisations. This allows to provide results for the full ILC programme, i.e.\ from 250\,GeV to 1\,TeV, as well as to give approximate results for other planned lepton colliders.

    ↳ hep-exhep-phPRD(2020)·59 citations
20. 20*

    The Higgs phase as a spin glass, and the transition between varieties of confinement

    Jeff Greensite🇺🇸 · Kazue Matsuyama🇺🇸

    We propose that the Higgs phase of a gauge Higgs theory is the phase of spontaneously broken custodial symmetry, and present a new gauge invariant order parameter for custodial symmetry breaking which is very closely analogous to the Edwards-Anderson order parameter for spin glasses. Custodial symmetry is a global symmetry acting on the Higgs field alone, and we show here that the spin glass transition in gauge Higgs theories, from a QCD-like phase to a Higgs phase of broken custodial symmetry, coincides with the transition between two distinct types of confinement. These are color confinement in the Higgs phase, and a stronger version of confinement, which we have termed "separation-of-charge" confinement, in the QCD-like phase.

    ↳ hep-thcond-mat.dis-nncond-mat.stat-mechhep-lat+1PRD(2020)·30 citations
21. 21*

    Technical Proposal: FASERnu

    FASER Collaboration: Henso Abreu🇮🇱 · Marco Andreini🇨🇭 · Claire Antel🇨🇭 · Akitaka Ariga🇨🇭 · Tomoko Ariga🇯🇵 · Caterina Bertone🇨🇭 · Jamie Boyd🇨🇭 · Andy Buckley🇬🇧 · Franck Cadoux🇨🇭 · David W. Casper🇺🇸 · Francesco Cerutti🇨🇭 · Xin Chen🇨🇳 and 59 other authors

    FASERnu is a proposed small and inexpensive emulsion detector designed to detect collider neutrinos for the first time and study their properties. FASERnu will be located directly in front of FASER, 480 m from the ATLAS interaction point along the beam collision axis in the unused service tunnel TI12. From 2021-23 during Run 3 of the 14 TeV LHC, roughly 1,300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASERnu with TeV-scale energies. With the ability to observe these interactions, reconstruct their energies, and distinguish flavors, FASERnu will probe the production, propagation, and interactions of neutrinos at the highest human-made energies ever recorded. The FASERnu detector will be composed of 1000 emulsion layers interleaved with tungsten plates. The total volume of the emulsion and tungsten is 25cm x 25cm x 1.35m, and the tungsten target mass is 1.2 tonnes. From 2021-23, 7 sets of emulsion layers will be installed, with replacement roughly every 20-50 1/fb in planned Technical Stops. In this document, we summarize FASERnu's physics goals and discuss the estimates of neutrino flux and interaction rates. We then describe the FASERnu detector in detail, including plans for assembly, transport, installation, and emulsion replacement, and procedures for emulsion readout and analyzing the data. We close with cost estimates for the detector components and infrastructure work and a timeline for the experiment.

    ↳ physics.ins-dethep-exhep-ph176 citations
22. 22*

    The three-loop Adler $D$-function for $\mathcal{N}=1$ SQCD with various renormalization prescriptions

    S.S.Aleshin🇷🇺 · A.L.Kataev🇷🇺 · K.V.Stepanyantz🇷🇺

    The three-loop Adler $D$-function for $\mathcal{N}=1$ SQCD in the $\overline{\text{mbox}DR}$ scheme is calculated. It appears that the result does not satisfy NSVZ-like equation which relates the $D$-function to the anomalous dimension of the matter superfields. However this NSVZ-like equation can be restored by a special tuning of the renormalization scheme. Also we demonstrate that the $D$-function defined in terms of the bare coupling does not satisfy the NSVZ-like equation in the case of using the regularization by dimensional reduction. The scheme-dependence of the $D$-function written in the form of the $\beta$-expansion is briefly discussed.

    ↳ hep-thhep-ph0 citations
23. 23*

    Quantum Anomalies in String-Inspired Running Vacuum Universe: Inflation and Axion Dark Matter

    Spyros Basilakos🇬🇷 · Nick E. Mavromatos🇬🇧 · Joan Sola🇪🇸

    In this letter, we elaborate further on a Cosmological "Running-Vacuum" type model for the Universe, suggested previously by the authors within the context of a string-inspired effective theory in the presence of a Kalb-Ramond (KR) gravitational axion field which descends from the antisymmetric tensor of the massless gravitational string multiplet. In the presence of this field, which has anomalous CP violating interactions with the gravitons, primordial gravitational waves induce gravitational anomalies, which in turn are responsible for the appearance of $H^2$ and $H^4$ contributions to the vacuum energy density, these terms being characteristic of generic "running-vacuum-model (RVM) type", where $H$ is the Hubble parameter. In this work we prove in detail the appearance of the $H^4$ terms due to gravitational-anomaly-induced condensates in the energy density of the primordial Universe, which can self-consistently induce inflation, and subsequent exit from it, according to the generic features of RVM. We also argue in favour of the robustness of our results, which were derived within an effective low-energy field theory approach, against Ultra Violet completion of the theory. During the radiation and matter-dominated eras, gravitational anomalies cancel, as required for the consistency of the quantum matter/radiation field theory. However, chiral and QCD-axion-type anomalies survive and have important consequences for both cosmic magnetogenesis and axionic dark matter in the Universe. Finally, the stringy RVM scenario presented here predicts quintessence-like dynamical dark energy for the current Universe, which is compatible with the existing fitting analyses of such model against observations

    ↳ gr-qchep-phhep-thPLB(2020)·67 citations
24. 24*

    Skeptical combination of experimental results using JAGS/rjags with application to the K${}^{\pm }$ mass determination

    Giulio D'Agostini🇮🇹

    The question of how to combine experimental results that `appear' to be in mutual disagreement, treated in detail years ago in a previous paper, is revisited. The first novelty of the present note is the explicit use of graphical models, in order to make the deterministic and probabilistic links between the variables of interest more evident. Then, instead of aiming for results in closed formulae, the integrals of interest are evaluated by {\em Markov Chain Monte Carlo} (MCMC) sampling, with the algorithms (typically Gibbs Sampler) implemented in the package JAGS ("Just Another Gibbs Sampler"). For convenience, the JAGS functions are called from R scripts, thus gaining the advantage given by the rich collection of mathematical, statistical and graphical functions included in the R installation. The results of the previous paper are thus easily re-obtained and the method is applied to the determination of the charged kaon mass. This note, based on lectures to PhD students and young researchers has been written with a didactic touch, and the relevant JAGS/rjags code is provided. (A curious bias arising from the sequential application of the $\sqrt{{\chi }^2/\nu }$ scaling prescription to 'apparently' discrepant results, found here, will be discussed in more detail in a separate paper.)

    ↳ physics.data-anhep-ph10 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.