HEP Phenomenology·hep-ph

Wed·Jul 3, 2019Wednesday·July 3, 2019

29 papers—18 primary·11 cross-listed·reconstructed*

01*
Top quark decay at next-to-leading order in the Standard Model Effective Field Theory
Radja Boughezal🇺🇸 · Chien-Yi Chen🇺🇸 · Frank Petriello🇺🇸 · Daniel Wiegand🇺🇸
We consider top quark decay in the Standard Model Effective Field Theory (SMEFT). We present a calculation of the total decay width and the $W$ -boson helicity fractions at next-to-leading order (NLO) in SMEFT. Our result includes the complete set of contributing four-fermion operators in addition to QCD dipole operators and bottom-mass suppressed effects. We show that operators that first appear at NLO in the SMEFT can be bounded by the current data as well as future data from both a high-luminosity LHC and a potential $e^{+} e^{-}$ collider, demonstrating the importance of going beyond leading order when studying the SMEFT. We discuss technical aspects of our calculation that we believe will be useful in future higher-order studies of the SMEFT, in particular the treatment of $γ_{5}$ in loop diagrams.
hep-phPRD(2019)·45 citations
02*
Probing the strange content of the proton with charm production in charged current at LHeC
xFitter Developers' team: Hamed Abdolmaleki🇮🇷 · Valerio Bertone🇮🇹 · Daniel Britzger🇩🇪 · Stefano Camarda🇨🇭 · Amanda Cooper-Sarkar🇬🇧 · Achim Geiser🇩🇪 · Francesco Giuli🇮🇹 · Alexander Glazov🇩🇪 · Agnieszka Luszczak🇵🇱 · Ivan Novikov🇷🇺 · Fred Olness🇺🇸 · Andrey Sapronov🇷🇺 · Oleksandr Zenaiev🇩🇪
We study charm production in charged-current deep-inelastic scattering (DIS) using the xFitter framework. Recent results from the LHC have focused renewed attention on the determination of the strange-quark parton distribution function (PDF) and the DIS charm process provides important complementary constraints on this quantity. We examine the current PDF uncertainty, and use LHeC pseudodata to estimate the potential improvement from this proposed facility. As xFitter implements both fixed-flavor- and variable-flavor-number schemes, we can compare the impact of these different theoretical choices; this highlights some interesting aspects of multi-scale calculations. We find that the high-statistics LHeC data covering a wide kinematic range could substantially reduce the strange PDF uncertainty.
hep-phEPJC(2019)·10 citations
03*
Probing Non-Standard Neutrino Interactions with Supernova Neutrinos at Hyper-K
Minjie Lei🇺🇸 · Noah Steinberg🇺🇸 · James D. Wells🇺🇸
Non-standard neutrino self interactions (NSSI) could be stronger than Fermi interactions. We investigate the ability to constrain these four-neutrino interactions by their effect on the flux of neutrinos originating from a galactic supernova. In the dense medium of a core collapse supernova, these new self interactions can have a significant impact on neutrino oscillations, leading to changes at the flavor evolution and spectra level. We use simulations of the neutrino flux from a 13 solar mass, core collapse supernova at 10 kpc away, and numerically propagate these neutrinos through the stellar medium taking into account vacuum/MSW oscillations, SM $ν - ν$ scattering as well as $ν - ν$ interactions that arise from NSSI. We pass the resulting neutrino flux to a simulation of the future Hyper-Kamiokande detector to see what constraints on NSSI parameters are possible when the next galactic supernova becomes visible. We find that these constraints depend strongly on the neutrino mass hierarchy and if the NSSI is flavor-violating or preserving. Sensitivity to NSSI in the normal hierarchy (NH) at Hyper-K is limited by the experiment's ability to efficiently detect $ν_{e}$ , but deviations from no NSSI could be seen if the NSSI is particularly strong. In the inverted hierarchy (IH) scenario, Hyper-K can significantly improve constraints on flavor-violating NSSI down to $O (1 0^{- 1}) G_{F}$ .
hep-phJHEP(2020)·9 citations
04*
Polarization difference between hyperons and anti-hyperons induced by external magnetic field
Hai-Bo Li🇨🇳 · Xin-Xin Ma🇨🇳
We investigate the quantum correlated $Λ Λ ˉ$ production in the reaction $e^{+} e^{-} \to J / ψ \to Λ Λ ˉ$ . Since the $Λ$ or $Λ ˉ$ has a nonzero magnetic moment, its spin will undergo a Larmor precession in the magnetic field of the detector, such as the BESIII experiment. Because of the spin precession, the angular distribution of the $Λ$ and $Λ ˉ$ is slightly modified. Therefore, we obtain the corresponding term of the modified angular distribution due to the effect of the Larmor precession. We also estimate its potential effect on the measurements of $C P$ violation, as well as the decay asymmetry parameter and polarization of $Λ$ . The polarization of the $Λ$ or $Λ ˉ$ at the production vertex will rotate around the $B$ -field axis, over an angle depending on the flight length in, but it still could be measured by fit to the corrected angular distribution. Of important, We conclude that a nonzero $C P$ asymmetry of order $1 0^{- 4}$ will be caused once neglecting spin precession of the $Λ$ and $Λ ˉ$ in the $e^{+} e^{-} \to J / ψ \to Λ Λ ˉ$ process. The size of this $C P$ asymmetry is several times that of predicted within Standard Model in the hyperon decay. Although this effect is small, it will play an important role in future high precision experiments, such as the super-tau-charm factory.
hep-phhep-exPRD(2019)·10 citations
05*
Analysis on hadron spectra in heavy-ion collisions with a new non-extensive approach
Ke-Ming Shen🇭🇺
The transverse momentum spectra of identified charged hadrons stemming from high energy collisions at different beam energies are described by a new non-extensive distribution, the Kaniadakis $κ$ -distribution, with respect to the constraints in non-extensive quantum statistics. All fittings are also compared with the Tsallis distributions as well as the usual Boltzmann-Gibbs one. $χ^{2} / n df$ is also used to test the fitting goodness of all functions. Our results show that these different non-extensive approaches can be well applied in high energy collisions rather than the classical one. The Kaniadakis statistics is typically better applied into such systems with both positive and negative particles considered. This provides an alternative non-extensive view to study high energy physics. Analysis on the fitting parameters are present as well. The similar relationships of all functions remind us of the further understanding of the non-extensivity.
hep-phJ.Phys.G(2019)·3 citations
06*
Neutrino oscillations at dual baselines
Minseok Cho🇰🇷 · YeolLin ChoeJo🇰🇷 · Hye-Sung Lee🇰🇷 · Young-Min Lee🇰🇷 · Sushant K. Raut🇰🇷
Beam neutrino oscillation experiments typically employ only one detector at a certain baseline, apart from the near detector that measures the unoscillated neutrino flux at the source. Lately, there have been discussions of having detectors at two different baselines in one of the future long-baseline neutrino oscillation experiments. We study the potential advantage of a general dual-baseline system and perform analysis with a specific example of the envisioned T2HKK experiment. We introduce a new parameter to exploit the correlation between the oscillations at both baselines, and show how it can help in determining the mass hierarchy and the CP phase in the neutrino sector. Our study and findings can be generically used for any dual-baseline system.
hep-phhep-ex3 citations
07*
1+1 dimensional relativistic magnetohydrodynamics with longitudinal acceleration
Duan She🇨🇳 · Ze Fang Jiang🇨🇳 · De-fu Hou🇨🇳 · C. B. Yang🇨🇳
Non-central heavy-ion collisions generate the strongest magnetic field of the order of $1 0^{18} - 1 0^{19}$ Gauss due to the electric current produced by the positively charged spectators that travel at nearly the speed of light. Such transient electromagnetic fields may induce various novel effects in the hydrodynamic description of the quark gluon plasma for non-central heavy-ion collisions. We investigate the longitudinal acceleration effects on the 1+1 dimensional relativistic magnetohydrodynamics with transverse magnetic fields. We analyze the proper time evolution of the system energy density. We find that the longitudinal acceleration parameter $λ^{*}$ , magnetic field decay parameter $a$ , equation of state $κ$ , and initial magnetization $σ_{0}$ have nontrivial effects on the evolutions of the system energy density and temperature.
hep-phnucl-thPRD(2019)·12 citations
08*
$B_{s}^{*} \to l^{+} l^{-}$ decays in light of recent $B$ anomalies
Suman Kumbhakar🇮🇳 · Jyoti Saini🇮🇳
Some of the recent measurements in the neutral current sector $b \to s l^{+} l^{-}$ ( $l = e$ or $μ$ ) as well as in the charged current sector $b \to c τ ν ˉ$ show significant deviations from their Standard Model predictions. It has been shown that two different new physics solutions, in the form of vector and/or axial vector, can explain all the anomalies in $b \to s l^{+} l^{-}$ sector. We show that the muon longitudinal polarization asymmetry in $B_{s}^{*} \to μ^{+} μ^{-}$ decay is a good discriminant between the two solutions if it can be measured to a precision of $\sim 10%$ , provided the new physics Wilson coefficients are real. We also investigate the potential impact of $b \to c τ ν ˉ$ anomalies on $B_{s}^{*} \to τ^{+} τ^{-}$ decay. We consider a model where the new physics contributions to these two transitions are strongly correlated. We find that two orders of magnitude enhancement in the branching ratio of $B_{s}^{*} \to τ^{+} τ^{-}$ is allowed by the present $b \to c τ ν ˉ$ data.
hep-phhep-exSpringer Proc.Phys.(2021)·0 citations
09*
Study of a tri-direct littlest seesaw model at MOMENT
Jian Tang🇨🇳 · TseChun Wang🇨🇳
The flavour symmetry succeeds in explaining the current global fit results. Flavour-symmetry models can be tested by the future experiments that improve the precision of neutrino oscillation parameters, \textit{such as} the MuOn-decay MEdium baseline NeuTrino beam experiment (MOMENT). In this work, we consider tri-direct littlest seesaw (TDLS) models for a case study, and analyze how much MOMENT can extend our knowledge on the TDLS model. We find that measurements of $θ_{23}$ and $δ$ are crucial for MOMENT to exclude the model at more than $5 σ$ confidence level, if the best fit values in the last global analysis result is confirmed. Moreover, the $3 σ$ precision of model parameters can be improved at MOMENT by at least a factor of two. Finally, we project the surface at the $3 σ$ confidence level from the model-parameter space to the oscillation-parameter space, and find the potential of MOMENT to observe the sum rule between $θ_{23}$ and $δ$ predicted by TDLS.
hep-phhep-exNPB(2020)·2 citations
10*
Constraining gluon PDFs with quarkonium production
Melih Arslan Ozcelik🇫🇷
We explore how the positivity of the P_T-integrated eta_c-hadroproduction cross-section computed at NLO in alpha_s can set up constraints on the x-dependence of gluon PDFs at low scales.
hep-phPoS(2019)·11 citations
11*
Differential and total cross sections of high energy proton-proton scattering in holographic QCD
Akira Watanabe🇨🇳
The analysis on the high energy proton-proton scattering is presented, focusing on the Regge regime and considering the Pomeron exchange to describe the involved nonperturbative dynamics in the framework of holographic QCD. We combine the Reggeized spin-2 particle propagator and the proton gravitational form factor, which is obtained from the bottom-up AdS/QCD model, and calculate the differential and total cross sections. We explicitly demonstrate the comparison between our calculations and the currently available experimental data including the recent ones measured at $s = 13$ TeV by the TOTEM collaboration at the LHC. It is shown that our results are consistent with the data, which implies that the present framework works in the considered TeV scale.
hep-phhep-exnucl-exnucl-thPoS(2019)·3 citations
12*
$α_{s}$ (2019): Precision measurements of the QCD coupling
David d'Enterria · Stefan Kluth (eds.) · S. Alekhin🇩🇪 · P. A. Baikov🇷🇺 · A. Banfi🇬🇧 · F. Barreiro🇪🇸 · A. Bazavov🇺🇸 · S. Bethke🇩🇪 · J. Blümlein🇩🇪 · D. Boito🇧🇷 · N. Brambilla🇩🇪 · D. Britzger🇩🇪 and 41 other authors
This document collects a written summary of all contributions presented at the workshop " $α_{s}$ (2019): Precision measurements of the strong coupling" held at ECT* (Trento) in Feb. 11--15, 2019. The workshop explored in depth the latest developments on the determination of the QCD coupling $α_{s}$ from the key categories where high precision measurements are available: (i) lattice QCD, (ii) hadronic $τ$ decays, (iii) deep-inelastic scattering and parton distribution functions, (iv) event shapes, jet cross sections, and other hadronic final-states in $e^{+} e^{-}$ collisions, (v) Z boson and W boson hadronic decays, and (vi) hadronic final states in p-p collisions. The status of the current theoretical and experimental uncertainties associated to each extraction method, and future perspectives were thoroughly reviewed. Novel $α_{s}$ determination approaches were discussed, as well as the combination method used to obtain a world-average value of the QCD coupling at the Z mass pole.
hep-phhep-ex33 citations
13*
Is the X(3872) a bound state ?
Pablo G. Ortega🇪🇸 · Enrique Ruiz Arriola🇪🇸
All existing experimental evidence of the bound state nature of the $X (3872)$ relies on considering its decay products with a finite experimental spectral mass resolution which is typically $Δ m \geq 2$ MeV and much larger than its alleged binding energy, $B_{X} = 0.00 (18)$ MeV. On the other hand, we have found recently that there is a neat cancellation in the $1^{++}$ channel for the invariant $D D ˉ^{*}$ mass around the threshold between the continuum and bound state contribution. This is very much alike a similar cancellation in the proton-neutron continuum with the deuteron in the $1^{++}$ channel. Based on comparative fits of experimental cross section deuteron and $X (3872)$ prompt production in pp collisions data with a finite $p_{T}$ to a common Tsallis distribution we find a strong argument questioning the bound state nature of the state but also explaining the large observed production rate likely consistent with a half-bound state.
hep-phnucl-thCPC(2019)·11 citations
14*
Neutrino Masses from the Point of View of Economy and Simplicity
S. Bilenky🇷🇺
In the framework of such basic principles as local gauge invariance, unification of the weak and electromagnetic interactions and spontaneous symmetry breaking in the Standard Model the most economical and simplest possibilities are realized. We discuss the problem of neutrino masses from the point of view of economy and simplicity. It is unlikely that neutrino masses are of the same SM origin as masses of leptons and quarks. The Weinberg effective Lagrangian is the simplest and the most economical, beyond the Standard Model mechanism of the generation of small Majorana neutrino masses. The resolution of the sterile neutrino anomaly and observation of the neutrinoless double $β$ -decay would be crucial tests of this mechanism.
hep-phPhys.Part.Nucl.(2019)·6 citations
15*
Some decay properties of hidden-charm pentaquarks as baryon-meson molecules
M.B. Voloshin🇺🇸
It is pointed out that the previously suggested interpretation of the hidden-charm pentaquarks $P_{c} (4312)$ , $P_{c} (4440)$ and $P_{c} (4457)$ as molecular bound states of $Σ_{c} D ˉ$ and $Σ_{c} D ˉ^{*}$ baryon-meson pairs gives rise to specific relations for their decays. In particular, the heavy quark spin symmetry predicts ratios of rates of decays of each of the molecules to $J / ψ p$ and to $η_{c} p$ as well as of the decays to $Λ_{c} D ˉ$ and to $Λ_{c} D ˉ^{*}$ . Experimental studies of these relations would thus provide an indicative probe of the molecular structure.
hep-phhep-exPRD(2019)·69 citations
16*
Neutrino Masses and Mixing from Double Covering of Finite Modular Groups
Xiang-Gan Liu🇨🇳 · Gui-Jun Ding🇨🇳
We extend the even weight modular forms of modular invariant approach to general integral weight modular forms. We find that the modular forms of integral weights and level $N$ can be arranged into irreducible representations of the homogeneous finite modular group $Γ_{N}^{'}$ which is the double covering of $Γ_{N}$ . The lowest weight 1 modular forms of level 3 are constructed in terms of Dedekind eta-function, and they transform as a doublet of $Γ_{3}^{'} ≅ T^{'}$ . The modular forms of weights 2, 3, 4, 5 and 6 are presented. We build a model of lepton masses and mixing based on $T^{'}$ modular symmetry.
hep-phJHEP(2019)·190 citations
17*
Lorentz Violation and Radiative Corrections in Gauge Theories
A. F. Ferrari🇧🇷
Various studies have already considered radiative corrections in Lorentz-violating models unveiling many instances where a minimal or nonminimal operator generates, via loop corrections, a contribution to the photon sector of the Standard-Model Extension. However, an important fraction of this literature does not follow the widely accepted conventions and notations of the Standard-Model Extension, and this obscures the comparison between different calculations as well as possible phenomenological consequences. After reviewing some of these works, we uncover one example where a well defined loop correction to the $k_{F}$ coefficient, already presented in the literature, allows us to improve the bounds on one specific coefficient of the fermion sector of the Lorentz-violating QED extension.
hep-phhep-th0 citations
18*
Three-pion contribution to hadronic vacuum polarization
Martin Hoferichter🇺🇸 · Bai-Long Hoid🇩🇪 · Bastian Kubis🇩🇪
We address the contribution of the $3 π$ channel to hadronic vacuum polarization (HVP) using a dispersive representation of the $e^{+} e^{-} \to 3 π$ amplitude. This channel gives the second-largest individual contribution to the total HVP integral in the anomalous magnetic moment of the muon $(g - 2)_{μ}$ , both to its absolute value and uncertainty. It is largely dominated by the narrow resonances $ω$ and $ϕ$ , but not to the extent that the off-peak regions were negligible, so that at the level of accuracy relevant for $(g - 2)_{μ}$ an analysis of the available data as model independent as possible becomes critical. Here, we provide such an analysis based on a global fit function using analyticity and unitarity of the underlying $γ^{*} \to 3 π$ amplitude and its normalization from a chiral low-energy theorem, which, in particular, allows us to check the internal consistency of the various $e^{+} e^{-} \to 3 π$ data sets. Overall, we obtain $a_{μ}^{3 π} ∣_{\leq 1.8 GeV} = 46.2 (6) (6) \times 1 0^{- 10}$ as our best estimate for the total $3 π$ contribution consistent with all (low-energy) constraints from QCD. In combination with a recent dispersive analysis imposing the same constraints on the $2 π$ channel below $1 GeV$ , this covers nearly $80%$ of the total HVP contribution, leading to $a_{μ}^{HVP} = 692.3 (3.3) \times 1 0^{- 10}$ when the remainder is taken from the literature, and thus reaffirming the $(g - 2)_{μ}$ anomaly at the level of at least $3.4 σ$ . As side products, we find for the vacuum-polarization-subtracted masses $M_{ω} = 782.63 (3) (1) MeV$ and $M_{ϕ} = 1019.20 (2) (1) MeV$ , confirming the tension to the $ω$ mass as extracted from the $2 π$ channel.
hep-phhep-exhep-latnucl-thJHEP(2019)·498 citations
19*
Detectability of Collective Neutrino Oscillation Signatures in the Supernova Explosion of a 8.8 $M_{⊙}$ star
Hirokazu Sasaki🇯🇵 · Tomoya Takiwaki🇯🇵 · Shio Kawagoe🇯🇵 · Shunsaku Horiuchi🇺🇸 · Koji Ishidoshiro🇯🇵
In order to investigate the impact of collective neutrino oscillations (CNO) on the neutrino signal from a nearby supernova, we perform 3-flavor neutrino oscillation simulations employing the multiangle effect. The background hydrodynamic model is based on the neutrino hydrodynamic simulation of a 8.8 \Msun progenitor star. We find that CNO commences after some 100 ms post bounce. Before this, CNO is suppressed by matter-induced decoherence. In the inverted mass hierarchy, the spectrum of $ν ˉ_{e}$ becomes softer after the onset of CNO. To evaluate the detectability of this modification, we define a hardness ratio between the number of high energy neutrino events and low energy neutrino events adopting a fixed critical energy. We show that Hyper-Kamiokande (HK) can distinguish the effect of CNO for supernova distances out to $\sim 10$ kpc. On the other hand, for the normal mass hierarchy, the spectrum of $ν_{e}$ becomes softer after the onset of CNO, and we show that DUNE can distinguish this feature for supernova distances out to $\sim 10$ kpc. More work is necessary to optimize the best value of critical energy for maximum sensitivity. We also show that if the spectrum of $ν ˉ_{e}$ in HK becomes softer due to CNO, the spectrum of $ν_{e}$ in DUNE becomes harder, and vice versa. This synergistic observations in $ν ˉ_{e}$ and $ν_{e}$ , by HK and DUNE respectively, will be an intriguing opportunity to test the occurrence of CNO.
↳ astro-ph.HEhep-phPRD(2020)·22 citations
20*
Neutral B-meson mixing from full lattice QCD at the physical point
R. J. Dowdall🇬🇧 · C. T. H. Davies🇬🇧 · R. R. Horgan🇬🇧 · G. P. Lepage🇺🇸 · C. J. Monahan🇺🇸 · J. Shigemitsu🇺🇸 · M. Wingate🇬🇧
We calculate the bag parameters for neutral $B$ -meson mixing in and beyond the Standard Model, in full four-flavour lattice QCD for the first time. We work on gluon field configurations that include the effect of $u$ , $d$ , $s$ and $c$ sea quarks with the Highly Improved Staggered Quark (HISQ) action at three values of the lattice spacing and with three $u / d$ quark masses going down to the physical value. The valence $b$ quarks use the improved NRQCD action and the valence light quarks, the HISQ action. Our analysis was blinded. Our results for the bag parameters for all five operators are the most accurate to date. For the Standard Model operator between $B_{s}$ and $B_{d}$ mesons we find: $B^_{B_{s}} = 1.232 (53)$ , $B^_{B_{d}} = 1.222 (61)$ . Combining our results with lattice QCD calculations of the decay constants using HISQ quarks from the Fermilab/MILC collaboration and with experimental values for $B_{s}$ and $B_{d}$ oscillation frequencies allows determination of the CKM elements $V_{t s}$ and $V_{t d}$ . We find $V_{t s} = 0.04189 (93)$ , $V_{t d} = 0.00867 (23)$ and $V_{t s} / V_{t d} = 0.2071 (27)$ . Our results agree well (within $2 σ$ ) with values determined from CKM unitarity constraints based on tree-level processes (only). Using a ratio to $Δ M$ in which CKM elements cancel in the Standard Model, we determine the branching fractions $Br (B_{s} \to μ^{+} μ^{-}) = 3.81 (18) \times 1 0^{- 9}$ and $Br (B_{d} \to μ^{+} μ^{-}) = 1.031 (54) \times 1 0^{- 10}$ . We also give results for matrix elements of the operators $R_{0}$ , $R_{1}$ and $R ~_{1}$ that contribute to neutral $B$ -meson width differences.
↳ hep-lathep-phPRD(2019)·185 citations
21*
A Genetic Algorithm for Astroparticle Physics Studies
Xiao-Lin Luo🇨🇳 · Jie Feng🇨🇳 · Hong-Hao Zhang🇨🇳
Precision measurements of charged cosmic rays have recently been carried out by space-born (e.g. AMS-02), or ground experiments (e.g. HESS). These measured data are important for the studies of astro-physical phenomena, including supernova remnants, cosmic ray propagation, solar physics and dark matter. Those scenarios usually contain a number of free parameters that need to be adjusted by observed data. Some techniques, such as Markov Chain Monte Carlo and MultiNest, are developed in order to solve the above problem. However, it is usually required a computing farm to apply those tools. In this paper, a genetic algorithm for finding the optimum parameters for cosmic ray injection and propagation is presented. We find that this algorithm gives us the same best fit results as the Markov Chain Monte Carlo but consuming less computing power by nearly 2 orders of magnitudes.
↳ astro-ph.HEastro-ph.IMhep-exhep-phComput.Phys.Commun.(2020)·13 citations
22*
Electroweak pion-production on nuclei within the extended factorization scheme
Noemi Rocco🇺🇸 · Satoshi X. Nakamura🇨🇳 · T.-S. H. Lee🇺🇸 · Alessandro Lovato🇺🇸
We have applied the extended factorization scheme to investigate the electroweak pion production on nuclei. The ANL-Osaka model, which was obtained by analyzing the data of $π N$ , $γ N$ , $N (e, e^{'} π)$ and $N (ν, μ π)$ reactions up to invariant mass $W =$ 2 GeV, is used to generate the matrix elements of current operators relevant to pion-production off the nucleon. Medium effects on the $Δ$ (1232) component of meson-exchange current are included by using a $Δ$ -nucleus potential determined from the previous $Δ$ -hole model studies of pion-nucleus reactions. Nuclear correlations in the initial target state and in the spectator system(s) are modeled using realistic hole spectral functions. As a first step, we show that the data of $^{12}$ C $(e, e^{'})$ up to the $Δ$ (1232) region can be described reasonably well. The interplay between the pion production and two-body meson-exchange mechanisms is shown to be essential in improving the agreement with the data in the ``dip'' region, between the quasielastic and the $Δ$ (1232) peaks. Predictions for $^{12}$ C $(ν, μ π)$ have also been made. They can be used to estimate pion-emission rates in neutrino-nucleus cross section, which constitutes an important systematic uncertainty to the reconstructed neutrino energy. With further improvements of the Metropolis Monte-Carlo techniques to account for final states comprised of more than two particles, our approach can be employed up to $W =$ 2 GeV, where two-pion production and higher mass nucleon resonances must be included for analyzing the data from accelerator-based neutrino-oscillation experiments.
↳ nucl-thhep-phPRC(2019)·35 citations
23*
Bootstrapping Inflationary Correlators in Mellin Space
Charlotte Sleight🇺🇸 · Massimo Taronna🇺🇸
We develop a Mellin space approach to boundary correlation functions in anti-de Sitter (AdS) and de Sitter (dS) spaces. Using the Mellin-Barnes representation of correlators in Fourier space, we show that the analytic continuation between AdS $_{d + 1}$ and dS $_{d + 1}$ is encoded in a collection of simple relative phases. This allows us to determine the late-time tree-level three-point correlators of spinning fields in dS $_{d + 1}$ from known results for Witten diagrams in AdS $_{d + 1}$ by multiplication with a simple trigonometric factor. At four point level, we show that Conformal symmetry fixes exchange four-point functions both in AdS $_{d + 1}$ and dS $_{d + 1}$ in terms of the dual Conformal Partial Wave (which in Fourier space is a product of boundary three-point correlators) up to a factor which is determined by the boundary conditions. In this work we focus on late-time four-point correlators with external scalars and an exchanged field of integer spin- $ℓ$ . The Mellin-Barnes representation makes manifest the analytic structure of boundary correlation functions, providing an analytic expression for the exchange four-point function which is valid for general $d$ and generic scaling dimensions, in particular massive, light and (partially-)massless fields. When $d = 3$ we reproduce existing explicit results available in the literature for external conformally coupled and massless scalars. From these results, assuming the weak breaking of the de Sitter isometries, we extract the corresponding correction to the inflationary three-point function of general external scalars induced by a general spin- $ℓ$ field at leading order in slow roll. These results provide a step towards a more systematic understanding of de Sitter observables at tree level and beyond using Mellin space methods.
↳ hep-thastro-ph.COhep-phJHEP(2020)·267 citations
24*
Multi-TeV flaring in nearby High Energy Blazars: A photohadronic scenario
Sarira Sahu🇲🇽
Blazars are a subclass of AGN and flaring in multi-TeV gamma-ray seems to be the major activity in high energy blazars a subgrup of blazars. Flaring is also unpredictable and switches between quiescent and active states involving different time scales and fluxes. While in some high energy blazars a strong temporal correlation between X-ray and multi-TeV gamma-ray has been observed, outbursts in some other have no low energy counterparts and explanation of such extreme activity needs to be addressed through different mechanisms as it is not understood well. The extragalactic background light (EBL) plays an important role in the observation of these high energy gamma-rays as it attenuates through pair production of electron-positron and also changes the spectral shape of the high energy photons. In the context of the photohadronic model and taking EBL correction into account, flaring can be explained very well. In a series of papers we have developed this model to explain multi-TeV flaring events form many blazars. Here in this review, the photohadronic model is discussed and applied to explain the multi-TeV flaring from nearby high energy blazars: Markarian 421, Markarian 501 and 1ES1959+650.
↳ astro-ph.HEhep-phRev.Mex.Fis.(2019)·18 citations
25*
The unequal mass sunrise integral expressed through iterated integrals on $M_{1, 3}$
Christian Bogner🇩🇪 · Stefan Müller-Stach🇩🇪 · Stefan Weinzierl🇩🇪
We solve the two-loop sunrise integral with unequal masses systematically to all orders in the dimensional regularisation parameter $ε$ . In order to do so, we transform the system of differential equations for the master integrals to an $ε$ -form. The sunrise integral with unequal masses depends on three kinematical variables. We perform a change of variables to standard coordinates on the moduli space $M_{1, 3}$ of a genus one Riemann surface with three marked points. This gives us the solution as iterated integrals on $M_{1, 3}$ . On the hypersurface $τ = \mbox co n s t$ our result reduces to elliptic polylogarithms. In the equal mass case our result reduces to iterated integrals of modular forms.
↳ hep-thhep-phmath-phmath.MPNPB(2020)·120 citations
26*
Hybrid static potential flux tubes from SU(2) and SU(3) lattice gauge theory
Lasse Mueller🇩🇪 · Owe Philipsen🇩🇪 · Christian Reisinger🇩🇪 · Marc Wagner🇩🇪
We compute chromoelectric and chromomagnetic flux densities for hybrid static potentials in SU(2) and SU(3) lattice gauge theory. In addition to the ordinary static potential with quantum numbers $Λ_{η}^{ϵ} = Σ_{g}^{+}$ , we present numerical results for seven hybrid static potentials corresponding to $Λ_{η}^{(ϵ)} = Σ_{u}^{+}, Σ_{g}^{-}, Σ_{u}^{-}, Π_{g}, Π_{u}, Δ_{g}, Δ_{u}$ , where the flux densities of five of them are studied for the first time in this work. We observe hybrid static potential flux tubes, which are significantly different from that of the ordinary static potential. They are reminiscent of vibrating strings, with localized peaks in the flux densities that can be interpreted as valence gluons.
↳ hep-lathep-phPRD(2019)·26 citations
27*
Pion and kaon parton distribution functions from basis light front quantization and QCD evolution
Jiangshan Lan🇨🇳 · Chandan Mondal🇨🇳 · Shaoyang Jia🇺🇸 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸
We investigate the parton distribution functions (PDFs) of the pion and the kaon by combining quantum chromodynamics (QCD) evolution with the basis light front quantization. The initial PDFs result from the light front wave functions obtained by diagonalizing the effective Hamiltonian consisting of the holographic QCD confinement potential, a complementary longitudinal confinement potential, and the color-singlet Nambu--Jona-Lasinio interactions. The valence-quark PDF of the pion, after QCD evolution, is consistent with the result from the E-0615 experiment at Fermilab. Meanwhile, the pion structure function calculated from the PDFs agrees with the ZEUS and the H1 experiments at DESY-HERA for large $x$ . Additionally, the ratio of the up quark PDF of the kaon to that of the pion is in agreement with the NA-003 experiment at CERN. We also present the cross section for the pion-nucleus induced Drell-Yan process with the obtained pion PDFs supplemented by the PDFs of the target nuclei.
↳ nucl-thhep-phPRD(2020)·119 citations
28*
Distinguishing black holes from horizonless objects through the excitation of resonances during inspiral
Vitor Cardoso🇵🇹 · Adrian del Rio🇵🇹 · Masashi Kimura🇯🇵
How well is the vacuum Kerr geometry a good description of the dark, compact objects in our universe? Precision measurements of accreting matter in the deep infrared and gravitational-wave measurements of coalescing objects are finally providing answers to this question. Here, we study the possibility of resonant excitation of the modes of the central object -- taken to be very compact but horizonless -- during an extreme-mass-ratio inspiral. We show that for very compact objects resonances are indeed excited. However, the impact of such excitation on the phase of the gravitational-wave signal is negligible, since resonances are crossed very quickly during inspiral.
↳ gr-qcastro-ph.HEhep-phhep-thPRD(2019)·46 citations
29*
Novel color superconducting phases of $N$ = 4 super Yang-Mills at strong coupling
Oscar Henriksson🇫🇮 · Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮
We revisit the large- $N_{c}$ phase diagram of $N$ = 4 super Yang-Mills theory at finite $R$ -charge density and strong coupling, by means of the AdS/CFT correspondence. We conjecture new phases that result from a black hole shedding some of its charge through the nucleation of probe color D3-branes that remain at a finite distance from the black hole when the dual field theory lives on a sphere. In the corresponding ground states the color group is partially Higgsed, so these phases can be identified as having a type of color superconductivity. The new phases would appear at intermediate values of the $R$ -charge chemical potential and we expect them to be metastable but long-lived in the large- $N_{c}$ limit.
↳ hep-thhep-phJHEP(2019)·35 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.