Mon·Dec 25, 2017Monday·December 25, 2017

1. 01*

   LHC data and its impact on nCTEQ15 PDFs

   D. B. Clark🇺🇸 · E. Godat🇺🇸 · T. Jezo🇨🇭 · C. Keppel🇺🇸 · K. Kovarik🇩🇪 · A. Kusina🇵🇱 · F. Lyonnet🇺🇸 · J.G. Morfin🇺🇸 · F. I. Olness🇺🇸 · J.F. Owens🇺🇸 · I. Schienbein🇫🇷 · J. Y. Yu🇺🇸

   The LHC heavy ion data for W/Z production can provide new incisive information on the PDFs. This data is sensitive to the heavier quark flavors (strange and charm) in a high energy kinematic region; this can facilitate the determination of PDFs in the small x region where previous data was limited. At present, the flavor separation of the proton PDFs is dependent on DIS data from nuclear targets. Therefore, improved nuclear corrections can also yield enhanced flavor determination of both the proton and nuclear PDFs.

   hep-phPoS(2018)·0 citations
2. 02*

   Duration of Classicality of Homogeneous Condensates with Attractive Interactions

   Sankha Chakrabarty🇺🇸 · Seishi Enomoto🇺🇸 · Yaqi Han🇺🇸 · Pierre Sikivie🇺🇸 · Elisa Todarello🇺🇸

   Dark matter axions and other highly degenerate bosonic fluids are commonly described by classical field equations. In a recent paper \cite{BECprop} we calculated the duration of classicality of homogeneous condensates with attractive contact interactions and of self-gravitating homogeneous condensates in critical expansion. According to their classical equations of motion, such condensates persist forever. In their quantum evolution parametric resonance causes quanta to jump in pairs out of the condensate into all modes with wavevector less than some critical value. We estimated in each case the time scale over which the condensate is depleted and after which a classical description is invalid.

   hep-phastro-ph.COhep-th0 citations
3. 03*

   Nucleon shadowing effects in $Cu+Cu$ and $Au+Au$ collisions at RHIC within the HIJING code

   Khaled Abdel-Waged🇸🇦 · Nuha Felemban🇸🇦

   The centrality dependence of pseudorapidity density of charged particles ($d{N}_{ch}/d\eta$) in $Cu+Cu$ ($Au+Au$) collisions at RHIC energy of $\sqrt{s_{{}_{\mathrm{NN}}}}=22.4$ , $62.4$ and $200$ ($19.6$, $62.4$ and $200$) GeV, is investigated within an improved HIJING code. The standard HIJING model is enhanced by a prescription for collective nucleon-nucleon ($NN$) interactions and more modern parton distribution functions. The collective $NN$-interactions are used to induce both cascade and nucleon shadowing effects. We find collective cascade broadens the pseudorapidity distributions in the tails (at $|\eta |>y_{\mathrm{beam}}$) above $25-30\%$ collision centrality to be consistent with the $d{N}_{ch}/d\eta$ data at $\sqrt{s_{{}_{\mathrm{NN}}}}=19.6$, $22.4$, $62.4$ GeV. The overall contribution of nucleon shadowing is shown to depress the whole shape of $d{N}_{ch}/d\eta$ in the primary interaction region (at $|\eta |<y_{\mathrm{beam}}$) for semiperipheral ($20-25$ \%) and peripheral ($\ge 35-40$\%) $Cu+Cu$ ($Au+Au$) interactions at $\sqrt{s_{{}_{\mathrm{NN}}}}=200$ GeV, in accordance with the PHOBOS data.

   hep-phnucl-exnucl-thJ.Phys.G(2018)·3 citations
4. 04*

   Mending $\rho \pi \pi$ vertex through the $\pi a_1$ diagonalization

   A. A. Osipov🇷🇺

   The problem of the strong momentum dependence of the $\rho \pi \pi$-vertex in the extended Nambu -- Jona-Lasinio model is solved by an appropriate choice of fields for spin-1 particles. A corresponding phenomenological Lagrangian is derived. As straightforward applications, the decay widths of $\rho \to \pi \pi$, and $a_1\to \rho \pi$ transitions are calculated and compared with known empirical data and previous theoretical estimates.

   hep-ph0 citations
5. 05*

   Unbinned model-independent measurements with coherent admixtures of multibody neutral $D$ meson decays

   Anton Poluektov🇬🇧

   Various studies of Standard Model parameters involve measuring the properties of a coherent admixture of $D^0$ and ${\overline{D}}^0$ states. A typical example is the determination of the Unitarity Triangle angle $\gamma$ in the decays $B\to DK$, $D\to K_S^0{\pi }^{+}{\pi }^{-}$. A model-independent approach to perform this measurement is proposed that has superior statistical sensitivity than the well-established method involving binning of the $D\to K_S^0{\pi }^{+}{\pi }^{-}$ decay phase space. The technique employs Fourier analysis of the complex phase difference between $D^0$ and ${\overline{D}}^0$ decay amplitudes and can be easily generalised to other similar measurements, such as studies of charm mixing or determination of the angle $\beta$ from $B^0\to D{h}^0$ decays.

   hep-phhep-exEPJC(2018)·19 citations
6. 06*

   Non-extensivity of the QCD pT spectra

   T. Bhattacharyya🇿🇦 · J. Cleymans🇿🇦 · S. Mogliacci🇿🇦 · A.S. Parvan🇷🇺 · A.S. Sorin🇷🇺 · O.V. Teryaev🇷🇺

   We try to establish a connection between the hadronic distributions, in proton-proton collisions at very high transverse momentum $p_{\mathrm{T}}$, obtained via perturbative QCD and the Tsallis non extensive statistics. Our motivation is that while the former is expected to be valid at extremely high momentum, due to asymptotic freedom, the latter has been very successful in describing experimental spectra over a wide range of momentum. Matching the non extensive statistics with the asymptotic $p_{\mathrm{T}}$ behaviour expected from QCD leads to the value of $q=1.25$.

   hep-phEPJA(2018)·15 citations
7. 07*

   Multiple critical end points in magnetized three flavor quark matter

   Márcio Ferreira🇵🇹 · Pedro Costa🇵🇹 · Constança Providência🇵🇹

   The magnetized phase diagram for three-flavor quark matter is studied within the Polyakov extended Nambu--Jona-Lasinio model. The order parameters are analyzed with special emphasis on the strange quark condensate. We show that the presence of an external magnetic field induces several critical endpoints (CEPs) in the strange sector, which arise due to the multiple phase transitions that the strange quark undergoes. The spinodal and binodal regions of the phase transitions are shown to increase with external magnetic field strength. The influence of strong magnetic fields on the isentropic trajectories around the several CEPs is analyzed. A focusing effect is observed on the region towards the CEPs that are related with the strange quark phase transitions. Compared to the chiral transitions, the deconfinement transition turns out to be less sensitive to the external magnetic field and the crossover nature is preserved over the whole phase diagram.

   hep-phPRD(2018)·22 citations
8. 08*

   Magnetized QCD phase diagram

   Márcio Ferreira🇵🇹 · Pedro Costa🇵🇹 · Constança Providência🇵🇹

   Using the 2+1 flavor Nambu--Jona-Lasinio (NJL) model with the Polyakov loop, we determine the structure of the QCD phase diagram in an external magnetic field. Beyond the usual NJL model with constant couplings, we also consider a variant with a magnetic field dependent scalar coupling, which reproduces the Inverse Magnetic Catalysis (IMC) at zero chemical potential. We conclude that the IMC affects the location of the Critical End Point, and found indications that, for high enough magnetic fields, the chiral phase transition at zero chemical potential might change from an analytic to a first-order phase transition.

   hep-phActa Phys.Polon.Supp.(2017)·1 citation
9. 09*

   Magnetized QCD phase diagram: critical end points for the strange quark phase transition driven by external magnetic fields

   Pedro Costa🇵🇹 · Márcio Ferreira🇵🇹 · Constança Providência🇵🇹

   In this work we examine possible effects of an external magnetic field in the strongly interacting matter phase diagram. The study is performed using the Polyakov-Nambu-Jona-Lasinio model. Possible consequences of the inverse magnetic catalysis effect on the phase diagram at both finite chemical potential and temperature are analyzed. We devote special emphasis on how the location of the multiple critical end points (CEPs) change in a magnetized medium: the presence of an external magnetic field induces several CEPs in the strange sector, which arise due to the multiple phase transitions that the strange quark undergoes. We also study the deconfinement transition which turns out to be less sensitive to the external magnetic field when compared to the quark phase transitions. The crossover nature of the deconfinement is preserved over the whole phase diagram.

   hep-phPoS(2018)·2 citations
10. 10*

    Electromagnetic structure of nucleon and Roper in soft-wall AdS/QCD

    Thomas Gutsche🇩🇪 · Valery E. Lyubovitskij🇩🇪 · Ivan Schmidt🇨🇱

    We present an improved study of the electromagnetic form factors of the nucleon and of the Roper-nucleon transition using an extended version of the effective action of soft-wall AdS/QCD. We include novel contribution from additional non-minimal terms, which do not renormalize the charge and do not change the normalization of the corresponding form factors, but the inclusion of these terms results in an important contribution to the momentum dependence of the form factors and helicity amplitudes.

    hep-phPRD(2018)·40 citations
11. 11*

    Fluctuation and Dissipation of Axial Charge from Massive Quarks

    De-fu Hou🇨🇳 · Shu Lin🇨🇳

    In quantum chromodynamics (QCD), axial charge is known to be non-conserved due to chiral anomaly and non-vanishing quark mass. In this paper, we explore the role of quark mass in axial charge fluctuation and dissipation. We present two separate calculations of axial charge correlator, which describe dynamics of axial charge. The first is free quarks at finite temperature. We find that axial charge can be generated through effective quantum fluctuations in free theory. However the fluctuation does not follow a random walk behavior. Due to the presence of axial symmetry breaking mass term, the axial charge also does not settle asymptotically to the thermodynamic limit given by susceptibility. The second calculation is in weakly coupled quark gluon plasma (QGP). We find in the hard thermal loop (HTL) approximation, the quark-gluon interaction leads to random walk growth of axial charge, but dissipation is not visible. We estimate relaxation time scale for axial charge, finding it lies beyond the HTL regime.

    hep-phnucl-thPRD(2018)·23 citations
12. 12*

    A new insight into the phase transition in the early Universe with two Higgs doublets

    Jérémy Bernon🇫🇷 · Ligong Bian🇨🇳 · Yun Jiang🇩🇰

    We study the electroweak phase transition in the alignment limit of the CP-conserving two-Higgs-doublet model (2HDM) of Type I and Type II. The effective potential is evaluated at one-loop, where the thermal potential includes Daisy corrections and is reliably approximated by means of a sum of Bessel functions. Both 1-stage and 2-stage electroweak phase transitions are shown to be possible, depending on the pattern of the vacuum development as the Universe cools down. For the 1-stage case focused on in this paper, we analyze the properties of phase transition and discover that the field value of the electroweak symmetry breaking vacuum at the critical temperature at which the first order phase transition occurs is largely correlated with the vacuum depth of the 1-loop potential at zero temperature. We demonstrate that a strong first order electroweak phase transition (SFOEWPT) in the 2HDM is achievable and establish benchmark scenarios leading to different testable signatures at colliders. In addition, we verify that an enhanced triple Higgs coupling (including loop corrections) is a typical feature of the SFOPT driven by the additional doublet. As a result, SFOEWPT might be able to be probed at the LHC and future lepton colliders through Higgs pair production.

    hep-phJHEP(2018)·110 citations
13. 13*

    Features of Neutrino Mixing

    S. H. Chiu🇹🇼 · T. K. Kuo🇺🇸

    The elements (squared) of the neutrino mixing matrix are found to satisfy, as functions of the induced mass, a set of differential equations. They show clearly the dominance of pole terms when the neutrino masses "cross". Using the known vacuum mixing parameters as initial conditions, it is found that these equations have very good approximate solutions, for all values of the induced mass. The results are applicable to Long Baseline Experiments (LBL).

    hep-phPRD(2018)·18 citations
14. 14*

    Fine-tuning in scalar meson decay with bound-state corrections

    M. L. L. da Silva🇧🇷 · D. T. da Silva🇧🇷 · C. A. Z. Vasconcellos🇧🇷 · D. Hadjimichef🇧🇷

    The glueball-quarkonia mixture decay amplitude has been evaluated, in the literature, by diagrammatic techniques for drawing quark lines and the quark-gluon vertex. In this paper we use an alternative approach which consists in a mapping technique, the Fock-Tani formalism, in order to obtain an effective Hamiltonian starting from microscopic interactions. An extra effect is present in this formalism associated to the extended nature of mesons: bound-state corrections, which introduces an additional decay amplitude and sets a fine-tuning procedure for general meson decay calculations. The $f_0(1500)\to \pi \pi$ channel shall be considered as numerical example of the procedure.

    hep-phnucl-th0 citations
15. 15*

    New color-magnetic defects in dense quark matter

    Alexander Haber🇦🇹 · Andreas Schmitt🇬🇧

    Color-flavor locked (CFL) quark matter expels color-magnetic fields due to the Meissner effect. One of these fields carries an admixture of the ordinary abelian magnetic field and therefore flux tubes may form if CFL matter is exposed to a magnetic field, possibly in the interior of neutron stars or in quark stars. We employ a Ginzburg-Landau approach for three massless quark flavors, which takes into account the multi-component nature of color superconductivity. Based on the weak-coupling expressions for the Ginzburg-Landau parameters, we identify the regime where CFL is a type-II color superconductor and compute the radial profiles of different color-magnetic flux tubes. Among the configurations without baryon circulation we find a new solution that is energetically preferred over the flux tubes previously discussed in the literature in the parameter regime relevant for compact stars. Within the same setup, we also find a new defect in the 2SC phase, namely magnetic domain walls, which emerge naturally from the previously studied flux tubes if a more general ansatz for the order parameter is used. Color-magnetic defects in the interior of compact stars allow for sustained deformations of the star, potentially strong enough to produce detectable gravitational waves.

    hep-phastro-ph.HEnucl-thJ.Phys.G(2018)·20 citations
16. 16*

    Sauter-Schwinger pair creation dynamically assisted by a plane wave

    Greger Torgrimsson🇩🇪 · Christian Schneider🇩🇪 · Ralf Schützhold🇩🇪

    We study electron-positron pair creation by a strong and constant electric field superimposed with a weaker transversal plane wave which is incident perpendicularly (or under some angle). Comparing the fully non-perturbative approach based on the world-line instanton method with a perturbative expansion into powers of the strength of the weaker plane wave, we find good agreement - provided that the latter is carried out to sufficiently high orders. As usual for the dynamically assisted Sauter-Schwinger effect, the additional plane wave induces an exponential enhancement of the pair-creation probability if the combined Keldysh parameter exceeds a certain threshold.

    hep-phPRD(2018)·48 citations
17. 17*

    Weak Vector Boson Production with Many Jets at the LHC $\sqrt{s}=13$ TeV

    F. R. Anger🇩🇪 · F. Febres Cordero🇩🇪 · S. Höche🇺🇸 · D. Maître🇬🇧

    Signatures with an electroweak vector boson and many jets play a crucial role at the Large Hadron Collider, both in the measurement of Standard-Model parameters and in searches for new physics. Precise predictions for these multi-scale processes are therefore indispensable. We present next-to-leading order QCD predictions for $W^{\pm }/Z$+jets at $\sqrt{s}=13$ TeV, including up to five/four jets in the final state. All production channels are included and leptonic decays of the vector bosons are considered at the amplitude level. We assess theoretical uncertainties arising from renormalization- and factorization-scale dependence by considering fixed-order dynamical scales based on the $H_{\mathrm{T}}$ variable as well as on the MiNLO procedure. We also explore uncertainties associated to different choices of parton-distribution functions. We provide event samples that can be explored through publicly available $n$-tuple sets, generated with BlackHat in combination with SHERPA.

    hep-phhep-exPRD(2018)·18 citations
18. 18*

    Power corrections to TMD factorization for Z-boson production

    I. Balitsky🇺🇸 · A. Tarasov🇺🇸

    A typical factorization formula for production of a particle with a small transverse momentum in hadron-hadron collisions is given by a convolution of two leading-twist TMD parton densities with cross section of production of the final particle by the two partons. For practical applications at a given transverse momentum, though, one should estimate at what momenta the power corrections to TMD factorization formula due to higher-twist operators become essential. In this paper we calculate the first power corrections to TMD factorization formula for Z-boson production and Drell-Yan process in high-energy hadron-hadron collisions. At the leading order in $N_c$ power corrections are expressed in terms of leading-twist TMDs by QCD equations of motion.

    hep-phJHEP(2018)·70 citations
19. 19*

    Possible higher order phase transition in large-$N$ gauge theory at finite temperature

    Hiromichi Nishimura🇺🇸 · Robert D. Pisarski🇺🇸 · Vladimir V. Skokov🇺🇸

    We analyze the phase structure of $SU(\infty )$ gauge theory at finite temperature using matrix models. Our basic assumption is that the effective potential is dominated by double-trace terms for the Polyakov loops. As a function of the temperature, a background field for the Polyakov loop, and a quartic coupling, it exhibits a universal structure: in the large portion of the parameter space, there is a continuous phase transition analogous to the third-order phase transition of Gross, Witten and Wadia, but the order of phase transition can be higher than third. We show that different confining potentials give rise to drastically different behavior of the eigenvalue density and the free energy. Therefore lattice simulations at large $N$ could probe the order of phase transition and test our results.

    ↳ hep-thhep-lathep-phPoS(2018)·1 citation
20. 20*

    QCD phase diagram for nonzero isospin-asymmetry

    B. B. Brandt🇩🇪 · G. Endrodi🇩🇪 · S. Schmalzbauer🇩🇪

    The QCD phase diagram is studied in the presence of an isospin asymmetry using continuum extrapolated staggered quarks with physical masses. In particular, we investigate the phase boundary between the normal and the pion condensation phases and the chiral/deconfinement transition. The simulations are performed with a small explicit breaking parameter in order to avoid the accumulation of zero modes and thereby stabilize the algorithm. The limit of vanishing explicit breaking is obtained by means of an extrapolation, which is facilitated by a novel improvement program employing the singular value representation of the Dirac operator. Our findings indicate that no pion condensation takes place above $T\approx 160$ MeV and also suggest that the deconfinement crossover continuously connects to the BEC-BCS crossover at high isospin asymmetries. The results may be directly compared to effective theories and model approaches to QCD.

    ↳ hep-lathep-phnucl-thPRD(2018)·215 citations
21. 21*

    Quantum entanglement in de Sitter space from Stringy Axion: An analysis using $\alpha$ vacua

    Sayantan Choudhury🇮🇳 · Sudhakar Panda🇮🇳

    In this work, we study the phenomena of quantum entanglement by computing de Sitter entanglement entropy from von Neumann measure. For this purpose we consider a bipartite quantum field theoretic setup in presence of axion originating from $\mathbf{Type}\mathbf{II}\mathbf{B}$ string theory. We consider the initial vacuum to be CPT invariant non-adiabatic $\alpha$ vacua state under $\mathbf{SO}(1,4)$ ismometry, which is characterized by a real one-parameter family. To implement this technique we use a ${\mathbf{S}}^2$ which divide the de Sitter into two exterior and interior sub-regions. First, we derive the wave function of axion in an open chart for $\alpha$ vacua by applying Bogoliubov transformation on the solution for Bunch-Davies vacuum state. Further, we quantify the density matrix by tracing over the contribution from the exterior region. Using this result we derive entanglement entropy, R$\acute{e}$nyi entropy and explain the long-range quantum effects in primordial cosmological correlations. We also provide a comparison between the results obtained from Bunch-Davies vacuum and the generalized $\alpha$ vacua, which implies that the amount of quantum entanglement and the long-range effects are larger for non zero value of the parameter $\alpha$. Most significantly, our derived results for $\alpha$ vacua provides the necessary condition for generating non zero entanglement entropy in primordial cosmology.

    ↳ hep-thastro-ph.COgr-qchep-ph+1NPB(2019)·40 citations
22. 22*

    Heavy light tetraquarks from Lattice QCD

    Parikshit Junnarkar🇮🇳 · M Padmanath🇩🇪 · Nilmani Mathur🇮🇳

    We present preliminary results from a lattice calculation of tetraquark states in the charm and bottom sector of the type $ud\bar{b}\bar{b}$, $us\bar{b}\bar{b}$, $ud\bar{c}\bar{c}$ and $sc\bar{b}\bar{b}$. These calculations are performed on $N_f=2+1+1$ MILC ensembles with lattice spacing of $a=0.12\mathrm{fm}$ and $a=0.06\mathrm{fm}$. A relativistic action with overlap fermions is employed for the light and charm quarks while a non-relativistic action with non-perturbatively improved coefficients is used in the bottom sector. Preliminary results provide a clear indication of presence of energy levels below the relevant thresholds of different tetraquark states. While in double charm sector we find shallow bound levels, our results suggest deeply bound levels with double bottom tetraquarks.

    ↳ hep-lathep-phnucl-thEPJ Web Conf.(2018)·13 citations
23. 23*

    Spectroscopy of Charmed and Bottom Hadrons using Lattice QCD

    Sourav Mondal🇮🇳 · M. Padmanath🇩🇪 · Nilmani Mathur🇮🇳

    We present preliminary results on the light, charmed and bottom baryon spectra using overlap valence quarks on the background of 2+1+1 flavours HISQ gauge configurations of the MILC collaboration. These calculations are performed on three different gauge ensembles at three lattice spacings (a ~ 0.12 fm, 0.09 fm and 0.06 fm) and for physical strange, charm and bottom quark masses. The SU(2) heavy baryon chiral perturbation theory is used to extrapolate baryon masses to the physical pion mass and the continuum limit extrapolations are also performed. Our results are consistent with the well measured charmed baryons. We predict the masses of many other states which are yet to be discovered.

    ↳ hep-lathep-exhep-phnucl-thEPJ Web Conf.(2018)·4 citations
24. 24*

    Special functions, transcendentals and their numerics

    Jakob Ablinger🇦🇹 · Johannes Blumlein🇩🇪 · Mark Round🇦🇹 · Carsten Schneider🇦🇹

    Cyclotomic polylogarithms are reviewed and new results concerning the special constants that occur are presented. This also allows some comments on previous literature results using PSLQ.

    ↳ hep-thhep-phmath-phmath.MPPoS(2017)·12 citations
25. 25*

    The twelve-flavor $\mathbf{\beta }$-function and dilaton tests of the sextet scalar

    Zoltan Fodor🇩🇪 · Kieran Holland🇺🇸 · Julius Kuti🇺🇸 · Daniel Nogradi🇭🇺 · Chik Him Wong🇩🇪

    We discuss near-conformal gauge theories beyond the standard model (BSM) where interesting results on the twelve-flavor $\beta$-function of massless fermions in the fundamental representation of the SU(3) color gauge group and dilaton tests of the light scalar with two massless fermions in the two-index symmetric tensor (sextet) representation can be viewed as parts of the same BSM paradigm under investigation. We report results from high precision analysis of the twelve-flavor $\beta$-function \cite{Fodor:2016zil} refuting its published IRFP \cite{Cheng:2014jba,Hasenfratz:2016dou}. We present our objections to recent claims \cite{Hasenfratz:2017mdh,Hasenfratz:2017qyr} for non-universal behavior of staggered fermions used in our analysis. We also report our first analysis of dilaton tests of the light $0^{++}$ scalar in the sextet model and comment on related post-conference developments. The dilaton test is the main thrust of this conference contribution including presentation #405 on the $n_f=12$ $\beta$-function and presentation #260 on dilaton tests of the sextet model. They are both selected from the near-conformal BSM paradigm.

    ↳ hep-lathep-phEPJ Web Conf.(2018)·51 citations
26. 26*

    Fayet-Iliopoulos terms in supergravity without gauged R-symmetry

    Niccolò Cribiori🇮🇹 · Fotis Farakos🇧🇪 · Magnus Tournoy🇧🇪 · Antoine Van Proeyen🇧🇪

    We construct a supergravity-Maxwell theory with a novel embedding of the Fayet-Iliopoulos D-term, leading to spontaneous supersymmetry breaking. The gauging of the R-symmetry is not required and a gravitino mass is allowed for a generic vacuum. When matter couplings are introduced, an uplift through a positive definite contribution to the scalar potential is obtained. We observe a notable similarity to the $\overline{D3}$ uplift constructions and we give a natural description in terms of constrained multiplets.

    ↳ hep-thhep-phJHEP(2018)·90 citations
27. 27*

    CaloGAN: Simulating 3D High Energy Particle Showers in Multi-Layer Electromagnetic Calorimeters with Generative Adversarial Networks

    Michela Paganini🇺🇸 · Luke de Oliveira🇺🇸 · Benjamin Nachman🇺🇸

    The precise modeling of subatomic particle interactions and propagation through matter is paramount for the advancement of nuclear and particle physics searches and precision measurements. The most computationally expensive step in the simulation pipeline of a typical experiment at the Large Hadron Collider (LHC) is the detailed modeling of the full complexity of physics processes that govern the motion and evolution of particle showers inside calorimeters. We introduce \textsc{CaloGAN}, a new fast simulation technique based on generative adversarial networks (GANs). We apply these neural networks to the modeling of electromagnetic showers in a longitudinally segmented calorimeter, and achieve speedup factors comparable to or better than existing full simulation techniques on CPU ($100\times$-$1000\times$) and even faster on GPU (up to $\sim 10^5\times$). There are still challenges for achieving precision across the entire phase space, but our solution can reproduce a variety of geometric shower shape properties of photons, positrons and charged pions. This represents a significant stepping stone toward a full neural network-based detector simulation that could save significant computing time and enable many analyses now and in the future.

    ↳ hep-excs.LGhep-phstat.MLPRD(2018)·325 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.