Thu·Aug 19, 2021Thursday·August 19, 2021

1. 01*

   On improving NLO merging for $t\bar{t}W$ production

   Rikkert Frederix🇸🇪 · Ioannis Tsinikos🇸🇪

   We introduce an improvement to the FxFx matrix element merging procedure for $pp\to t\bar{t}W$ production at NLO in QCD with one and/or two additional jets. The main modification is an improved treatment of jets that are not logarithmically enhanced in the low transverse-momentum regime. We provide predictions for the inclusive cross section and the $t\bar{t}W$ differential distributions including parton-shower effects. Taking also the NLO EW corrections into account, this results in the most-accurate predictions for this process to date. We further proceed to include the on-shell LO decays of the $t\bar{t}W$ including the tree-level spin correlations within the narrow-width approximation, focusing on the multi-lepton signatures studied at the LHC. We find a $\sim 30\%$ increase over the NLO QCD prediction and large non-flat $K$-factors to differential distributions.

   hep-phhep-exJHEP(2021)·104 citations
2. 02*

   Light Dark Matter Through the Quark Axial-Vector Current Portal

   Dillon Berger🇺🇸

   We consider a model in which dark matter is a light (350 MeV) Dirac fermion which couples to quarks as an axial-vector current. At center-of-mass (CM) energies below the confinement scale, such a DM interaction structure may be described through its low energy effective couplings to mesons. In this paper we focus on dark matter annihilation into these final state mesons, and its resulting photon spectrum. We present a coarse-grained approach for analyzing our model in which we argue the meson spectrum solely from kinematics and symmetries and thereby estimate the total DM annihilation cross section that corresponds to a given expected photon signal. We then corroborate and refine these findings with the more systematic approach of the chiral Lagrangian description of the model, since the CM energies we consider admit such a perturbative treatment. In both cases, we obtain constraints on the model by comparing the estimated photon signals to current and future observations, and show that the axial-vector DM portal is significantly more conducive to photon production for lighter forms of dark matter than a pure vector-like portal; establishing itself as a prime candidate for indirect detection probes with significant discovery reach.

   hep-ph0 citations
3. 03*

   WG2 Summary: Small-x, Diffraction and Vector Mesons

   Tolga Altinoluk🇵🇱 · Marta Luszczak🇵🇱 · Daniel Tapia Takaki🇺🇸

   Here we briefly summarize the contributions to Working Group 2: Small-x, Diffraction and Vector Mesons, at the DIS2021 Workshop.

   hep-phhep-exhep-thSciPost Phys.Proc.(2022)·0 citations
4. 04*

   Remarks on inverse electrodynamics

   Patricio Gaete🇨🇱 · José A. Helayël-Neto🇧🇷

   We study physical aspects for a new nonlinear electrodynamics (inverse electrodynamics). It is shown that this new electrodynamics displays the vacuum birefringence phenomenon in the presence of external magnetic field, hence we compute the bending of light. Afterwards we compute the lowest-order modification to the interaction energy within the framework of the gauge-invariant but path-dependent variables formalism. Our calculations show that the interaction energy contains a long-range ({1 \mathord{\left/ {\vphantom {1 {{r^5}}}} \right.\kern-\nulldelimiterspace} {{r^5}}}-type) correction to the Coulomb potential.

   hep-phhep-thEPJC(2021)·11 citations
5. 05*

   Vision for QCD to the 2030s and Beyond

   George Sterman🇺🇸

   In this closing talk of the DIS 2021 Workshop, I review some of the lessons we've learned about quantum chromodynamics, and reflect on what we may hope to learn in the coming years.

   hep-phSciPost Phys.Proc.(2022)·2 citations
6. 06*

   Two dark matter candidates: the case of inert doublet and singlet scalars

   G. Belanger🇫🇷 · A. Mjallal🇫🇷 · A. Pukhov🇷🇺

   We consider a multi-component dark matter model where the dark sector contains a scalar doublet and a complex scalar singlet. We impose a discrete $Z_4$ symmetry to ensure such that the lightest component of the doublet, $\tilde{A}$, and the singlet, $\tilde{S}$, are both stable. Interactions between the dark sectors impact significantly dark matter observables, they allow in particular to significantly relax the direct detection constraints on the model. To determine the parameter space that satisfies relic density, theoretical and collider constraints as well as direct and indirect detection limits, we perform two separate scans, the first includes the full parameter space of the model while the second is dedicated to scenarios with a compressed inert doublet spectrum. In the first case we find that the singlet is generally the dominant dark matter component while in the compressed case the doublet is more likely to be the dominant dark matter component. In both cases we find that the two dark matter particles can have masses that ranges from around $m_h/2$ to over the TeV scale. We emphasize the interplay between cosmological astrophysical and collider constraints and show that a large fraction of the parameter space that escapes current constraints is within the sensitivity reach of future detectors such as XENON-nT, Darwin or CTA. Important collider signatures are mostly found in the compressed spectrum case with the possibility of probing the model with searches for heavy stable charged particles and disappearing tracks. We also show that semi-annihilation processes such as $\tilde{S}\tilde{S}\to \tilde{A}Z$ could give the dominant signature in indirect detection searches.

   hep-phPRD(2022)·45 citations
7. 07*

   Nucleon decay in a minimal non-SUSY GUT with predicted quark-lepton Yukawa ratios

   Stefan Antusch🇨🇭 · Kevin Hinze🇨🇭

   We investigate the predictions for various nucleon decay rates and their ratios in non-supersymmetric SU(5) Grand Unified Theories (GUTs) where the masses of the third and second family down-type quarks and charged leptons each stem dominantly from single GUT operators. Extending the Georgi-Glashow SU(5) model by a 45-dimensional GUT-Higgs representation, the gauge couplings can meet at the high scale $M_{\mathrm{GUT}}$ and the GUT scale predictions $y_{\tau }/y_b=3/2$ and $y_{\mu }/y_s=9/2$ can emerge within single operator dominance. Explaining the observed neutrino masses via the type I seesaw mechanism by adding SU(5) singlet fermion representations and taking their renormalization group effects into account, we show that these predictions can lead to viable low scale second and third family down-type quark and charged lepton masses. To investigate nucleon decay predictions, we extend the minimal scenario to two "toy models" towards explaining quark and lepton masses and mixings with different flavor structure, and perform Markov Chain Monte Carlo (MCMC) analyses confronting the models with the available experimental data. We show that if several nucleon decay channels are observed, the ratios between their partial decay rates can serve as "fingerprints", allowing to separate between GUT models with different flavor structure.

   hep-phNPB(2022)·16 citations
8. 08*

   Resolving the $(g-2{)}_{\mu }$ Discrepancy with $\mathcal{F}$-$SU$(5) Intersecting D-branes

   Joseph L. Lamborn🇺🇸 · Tianjun Li🇨🇳 · James A. Maxin🇺🇸 · Dimitri V. Nanopoulos🇺🇸

   A discrepancy between the measured anomalous magnetic moment of the muon $(g-2{)}_{\mu }$ and computed Standard Model value now stands at a combined $4.2\sigma$ following experiments at Brookhaven National Lab (BNL) and the Fermi National Accelerator Laboratory (FNAL). A solution to the disagreement is uncovered in flipped $SU(5)$ with additional TeV-Scale vector-like $10+\overline{10}$ multiplets and charged singlet derived from local F-Theory, collectively referred to as $\mathcal{F}$-$SU(5)$. Here we engage general No-Scale supersymmetry (SUSY) breaking in $\mathcal{F}$-$SU(5)$ D-brane model building to alleviate the $(g-2{)}_{\mu }$ tension between the Standard Model and observations. A robust $\Delta a_{\mu }$(SUSY) is realized via mixing of $M_5$ and $M_{1X}$ at the secondary $SU(5)\times U(1{)}_X$ unification scale in $\mathcal{F}$-$SU(5)$ emanating from $SU(5)$ breaking and $U(1{)}_X$ flux effects. Calculations unveil $\Delta a_{\mu }(\mathrm{SUSY})=19.0-22.3\times 10^{-10}$ for gluino masses of $M(\tilde{g})=2.25-2.56$ TeV and higgsino dark matter, aptly residing within the BNL+FNAL $1\sigma$ mean. This $(g-2{)}_{\mu }$ favorable region of the model space also generates the correct light Higgs boson mass and branching ratios of companion rare decay processes, and is further consistent with all LHC Run 2 constraints. Finally, we examine the heavy SUSY Higgs boson in light of recent LHC searches for an extended Higgs sector.

   hep-phhep-exJHEP(2021)·15 citations
9. 09*

   Critical point and Bose-Einstein condensation in pion matter

   V. A. Kuznietsov🇺🇦 · O. S. Stashko🇺🇦 · O. V. Savchuk🇩🇪 · M. I. Gorenstein🇺🇦

   The Bose-Einstein condensation and the liquid-gas first order phase transition are studied in the interacting pion matter. Two phenomenological models are used: the mean-field model and the hybrid model. Free model parameters are fixed by fitting the lattice QCD data on the pion Bose condensate density at zero temperature. In spite of some minor differences the two model demonstrate an identical qualitative and very close quantitative behavior for the thermodynamic functions and electric charge fluctuations. A peculiar property of the considered models is an intersection of the Bose-Einstein condensation line and the line of the first order phase transition at the critical end point.

   hep-phnucl-thPRC(2021)·8 citations
10. 10*

    Mining for Gluon Saturation at Colliders

    Astrid Morreale🇺🇸 · Farid Salazar🇺🇸

    Quantum chromodynamics (QCD) is the theory of strong interactions of quarks and gluons collectively called partons, the basic constituents of all nuclear matter. Its non-abelian character manifests in nature in the form of two remarkable properties: color confinement and asymptotic freedom. At high energies, perturbation theory can result in the growth and dominance of very gluon densities at small-x. If left uncontrolled, this growth can result in gluons eternally growing violating a number of mathematical bounds. The resolution to this problem lies by balancing gluon emissions by recombinating gluons at high energies : phenomena of gluon saturation. High energy nuclear and particle physics experiments have spent the past decades quantifying the structure of protons and nuclei in terms of their fundamental constituents confirming predicted extraordinary behavior of matter at extreme density and pressure conditions. In the process they have also measured seemingly unexpected phenomena. We will give a state of the art review of the underlying theoretical and experimental tools and measurements pertinent to gluon saturation physics. We will argue for the need of high energy electron-proton/ion colliders such as the proposed EIC (USA) and LHeC (Europe) to consolidate our knowledge of QCD in the small x kinematic domains.

    hep-phhep-exnucl-exnucl-thUniverse(2021)·168 citations
11. 11*

    Deep-inelastic electron-deuteron scattering with spectator nucleon tagging at the electron-ion collider. Extracting free nucleon structure

    Alexander Jentsch🇺🇸 · Zhoudunming Tu🇺🇸 · Christian Weiss🇺🇸

    Background: Deep-inelastic scattering (DIS) on the deuteron with spectator nucleon tagging represents a unique method for extracting the free neutron structure functions and exploring the nuclear modifications of bound protons and neutrons. The detection of the spectator (with typical momenta $\lesssim$ 100 MeV/c in the deuteron rest frame) controls the nuclear configuration during the DIS process and enables a differential analysis of nuclear effects. At the future electron-ion collider (EIC) such measurements will be performed using far-forward detectors. Purpose: Simulate deuteron DIS with proton or neutron tagging with the baseline EIC far-forward detector design. Quantify detector acceptance and resolution effects. Study feasibility of free nucleon structure extraction using pole extrapolation in the spectator momentum. Methods: DIS events with proton and neutron spectators are generated using the BeAGLE Monte Carlo generator. The spectator nucleon momentum is reconstructed including effects of detector acceptance and resolution. Pole extrapolation is performed under realistic conditions. The free nucleon structure extraction is validated by comparing with the input model. Results: Proton and neutron spectator detection is possible over the full transverse momentum range $0<p_T<100$ MeV/c needed for pole extrapolation. Resolution effects on the distributions before corrections are ~10% for proton and ~30 for neutron spectators. The overall accuracy of nucleon structure extraction is expected to be at the few-percent level. Conclusions: Free neutron structure extraction through proton tagging and pole extrapolation is feasible with the baseline EIC far-forward detector design. The corresponding extraction of free proton structure through neutron tagging provides a reference point for future studies of nuclear modifications.

    hep-phhep-exnucl-exPRC(2021)·24 citations
12. 12*

    Additional Baryons and Mesons

    Paul H. Frampton🇮🇹

    In a particle theory model whose most readily discovered new particle is the $\sim 1$TeV bilepton resonance in same-sign leptons, currently being sought at CERN's LHC, there exist three quarks $\mathcal{D},\mathcal{S},\mathcal{T}$ which will be bound by QCD into baryons and mesons. We consider the decays of these additional baryons and mesons whose detailed experimental study will be beyond the reach of the 14 TeV CERN collider and accessible only at an O(100 TeV) collider.

    hep-phMod.Phys.Lett.A(2021)·2 citations
13. 13*

    Multichannel decay law

    Francesco Giacosa🇵🇱

    It is well known, both theoretically and experimentally, that the survival probability for an unstable quantum state, formed at $t=0,$ is not a simple exponential function, even if the latter is a good approximation for intermediate times. Typically, unstable quantum states/particles can decay in more than a single decay channel. In this work, the general expression for the probability that an unstable state decays into a certain $i$-th channel between the initial time $t=0$ and an arbitrary $t>0$ is provided, both for nonrelativistic quantum states and for relativistic particles. These partial decay probabilities are also not exponential and their ratio turns out to be not a simple constant, as it would be in the exponential limit. Quite remarkably, these deviations may last relatively long, thus making them potentially interesting in applications. Thus, multichannel decays represent a promising and yet unexplored framework to search for deviations from the exponential decay law in quantum mechanical systems, such as quantum tunnelling, and in the context of particle decays.

    ↳ quant-phhep-phPLB(2022)·16 citations
14. 14*

    Interplay between core and corona components in high-energy nuclear collisions

    Yuuka Kanakubo🇯🇵 · Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵

    We establish the updated version of dynamical core--corona initialization framework (DCCI2) as a unified description from small to large colliding systems and from low to high transverse momentum ($p_T$) regions. Using DCCI2, we investigate effects of interplay between locally equilibrated and non-equilibrated systems, in other words, core and corona components in high-energy nuclear collisions. Given experimental multiplicity distributions and yield ratios of $\Omega$ baryons to charged pions as inputs, we extract the fraction of core and corona components in p+p collisions at $\sqrt{s}=7$ TeV and Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV. We find core contribution overtakes corona contribution as increasing multiplicity above $⟨d{N}_{\mathrm{ch}}/d\eta {⟩}_{|\eta |<0.5}\sim 18$ regardless of the collision system or energy. We also see that the core contribution exceeds the corona contribution only in 0.0-0.95\% multiplicity class in p+p collisions. Notably, there is a small enhancement of corona contribution with $\sim 20$\% below $p_T\sim 1$ GeV even in minimum bias Pb+Pb collisions. We find that the corona contribution at low $p_T$ gives $\sim 15$-$38$ $\%$ correction on $v_2\{2\}$ at $N_{\mathrm{ch}}\lesssim 370$. This raises a problem in conventional hydrodynamic analyses in which low $p_T$ soft hadrons originate solely from core components. We finally scrutinize the roles of string fragmentation and the longitudinal expansion in the transverse energy per unit rapidity, which is crucial in initial conditions for hydrodynamics from event generators based on string models.

    ↳ nucl-thhep-phnucl-exPRC(2022)·45 citations
15. 15*

    Probing Ultra-light Axion Dark Matter from 21cm Tomography using Convolutional Neural Networks

    Cristiano G. Sabiu🇰🇷 · Kenji Kadota🇰🇷 · Jacobo Asorey🇰🇷 · Inkyu Park🇰🇷

    We present forecasts on the detectability of Ultra-light axion-like particles (ULAP) from future 21cm radio observations around the epoch of reionization (EoR). We show that the axion as the dominant dark matter component has a significant impact on the reionization history due to the suppression of small scale density perturbations in the early universe. This behavior depends strongly on the mass of the axion particle. Using numerical simulations of the brightness temperature field of neutral hydrogen over a large redshift range, we construct a suite of training data. This data is used to train a convolutional neural network that can build a connection between the spatial structures of the brightness temperature field and the input axion mass directly. We construct mock observations of the future Square Kilometer Array survey, SKA1-Low, and find that even in the presence of realistic noise and resolution constraints, the network is still able to predict the input axion mass. We find that the axion mass can be recovered over a wide mass range with a precision of approximately 20\%, and as the whole DM contribution, the axion can be detected using SKA1-Low at 68\% if the axion mass is $M_X<1.86\times 10^{-20}$eV although this can decrease to $M_X<5.25\times 10^{-21}$eV if we relax our assumptions on the astrophysical modeling by treating those astrophysical parameters as nuisance parameters.

    ↳ astro-ph.COhep-phhep-thJCAP(2022)·8 citations
16. 16*

    Symmetries of temporal correlators and the nature of hot QCD

    L. Ya. Glozman🇦🇹 · Y. Aoki🇯🇵 · S. Hashimoto🇯🇵 · C. Rohrhofer🇯🇵

    The temperature of the chiral restoration phase transition at 130 MeV as well as the temperature of the center symmetry ("deconfinement") phase transition in a pure glue theory at 300 MeV are two independent temperatures and their interplay determines a structure of different regimes of hot QCD. Given a chiral spin symmetry of the color charge and of the chromoelectric interaction we can conclude from observed symmetries of spatial and temporal correlators of N_F=2 QCD with domain wall Dirac operator at physical quark masses that above the chiral symmetry restoration crossover around T_pc but below rougly 3T_pc there should exist an intermediate regime (the stringy fluid) of hot QCD that is characterized by approximate chiral spin symmetry and where degrees of freedom are chirally symmetric quarks bound into color singlet objects by the chromoelectric field. Above this intermediate regime the color charge and the chromoelectric field are Debye screened and one observes a transition to QGP with magnetic confinement.

    ↳ hep-lathep-phhep-thnucl-thPoS(2022)·2 citations
17. 17*

    Deriving dilaton potential in improved holographic QCD from meson spectrum

    Koji Hashimoto🇯🇵 · Keisuke Ohashi🇯🇵 · Takayuki Sumimoto🇯🇵

    We derive an explicit form of the dilaton potential in improved holographic QCD (IHQCD) from the experimental data of the $\rho$ meson spectrum. For this purpose we make use of the emergent bulk geometry obtained by deep learning from the hadronic data in arXiv:2005.02636. Requiring that the geometry is a solution of an IHQCD derives the corresponding dilaton potential backwards. This determines the bulk action in a data-driven way, which enables us at the same time to ensure that the deep learning proposal is a consistent gravity. Furthermore, we find that the resulting potential satisfies the requirements normally imposed in IHQCD, and that the holographic Wilson loop for the derived model exhibits quark confinement.

    ↳ hep-thhep-phPRD(2022)·32 citations
18. 18*

    Bottomonium resonances from lattice QCD static-static-light-light potentials

    Lasse Mueller🇩🇪 · Pedro Bicudo🇵🇹 · Nuno Cardoso🇵🇹 · Marc Wagner🇩🇪

    We study $I=0$ quarkonium resonances decaying into pairs of heavy-light mesons using static-static-light-light potentials from lattice QCD. To this end, we solve a coupled channel Schrödinger equation with a confined quarkonium channel and channels with a heavy-light meson pair to compute phase shifts and $\text{mbox}T$ matrix poles for the lightest decay channel. We discuss our results for $S$, $P$, $D$ and $F$ wave states in the context of corresponding experimental results, in particular for ${\rm Y}(10753)$ and ${\rm Y}(10860)$.

    ↳ hep-lathep-phPoS(2022)·1 citation
19. 19*

    First order framework for vortices in generalized Maxwell-Chern-Simons models without a neutral field

    I. Andrade🇧🇷 · D. Bazeia🇧🇷 · M.A. Liao🇧🇷 · M.A. Marques🇧🇷 · R. Menezes🇧🇷

    This work introduces a procedure to obtain vortex configurations described by first order equations in generalized Maxwell-Chern-Simons models without the inclusion of a neutral field. The results show that the novel methodology is capable of inducing important modification in the vortex core, leading to vortex configurations with unconventional features.

    ↳ hep-thhep-phMod.Phys.Lett.A(2022)·3 citations
20. 20*

    Bottomonium suppression and flow in heavy-ion collisions

    Michael Strickland🇺🇸

    The strong suppression of bottomonia production in ultra-relativistic heavy-ion collisions is a smoking gun for the creation of a deconfined quark-gluon plasma (QGP). In this proceedings contribution, I review recent work that aims to provide a more comprehensive and systematic understanding of bottomonium dynamics in the QGP through the use of pNRQCD and an open quantum systems approach. This approach allows one to evolve the heavy-quarkonium reduced density matrix, taking into account non-unitary effective Hamiltonian evolution of the wave-function and quantum jumps between different angular momentum and color states. In the case of a strong coupled QGP in which E << T,m_D << 1/a_0, the corresponding evolution equation is Markovian and can therefore be mapped to a Lindblad evolution equation. To solve the resulting Lindblad equation, we make use of a stochastic unraveling called the quantum trajectories algorithm and couple the non-abelian quantum evolution to a realistic 3+1D viscous hydrodynamical background. Using a large number of Monte-Carlo sampled bottomonium trajectories, we make predictions for bottomonium R_AA and elliptic flow as a function of centrality and transverse momentum and compare to data collected by the ALICE, ATLAS, and CMS collaborations.

    ↳ nucl-thhep-phEPJ Web Conf.(2022)·2 citations
21. 21*

    The Global 21 cm Signal of a Network of Cosmic String Wakes

    Oscar F. Hernández🇨🇦

    In previous works we discussed the 21 cm signature of a single cosmic string wake. However the 21 cm brightness temperature is influenced by a network of cosmic string wakes, and not one single wake. In this work we consider the signal from a network of wakes laid down during the matter era. We also improve on the previous calculation of a single wake signature. Finally we calculate the enhancement of the global 21 cm brightness temperature due to a network of wakes and discuss its affects of the signal measured in the Wouthuysen-Field absorption trough. We estimated that for string tensions between $10^{-8}$ to $10^{-7}$ there would be between a 10% to a factor 2 enhancement in the signal.

    ↳ astro-ph.COhep-phhep-thMNRAS(2021)·4 citations
22. 22*

    Toward emulating nuclear reactions using eigenvector continuation

    C. Drischler🇺🇸 · M. Quinonez🇺🇸 · P. G. Giuliani🇺🇸 · A. E. Lovell🇺🇸 · F. M. Nunes🇺🇸

    We construct an efficient emulator for two-body scattering observables using the general (complex) Kohn variational principle and trial wave functions derived from eigenvector continuation. The emulator simultaneously evaluates an array of Kohn variational principles associated with different boundary conditions, which allows for the detection and removal of spurious singularities known as Kohn anomalies. When applied to the $K$-matrix only, our emulator resembles the one constructed by Furnstahl et al. [Phys. Lett. B 809, 135719] although with reduced numerical noise. After a few applications to real potentials, we emulate differential cross sections for ${}^{40}$Ca$(n,n)$ scattering based on a realistic optical potential and quantify the model uncertainties using Bayesian methods. These calculations serve as a proof of principle for future studies aimed at improving optical models.

    ↳ nucl-thhep-lathep-phnucl-exPLB(2021)·69 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.