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Nuclear Theory·nucl-th

Thursday·July 12, 2018

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 06

    Constraining unintegrated gluon distributions from inclusive photon production in proton-proton collisions at the LHC

    Sanjin Benić🇯🇵 · Kenji Fukushima🇯🇵 · Oscar Garcia-Montero🇩🇪 · Raju Venugopalan🇺🇸

    We compute the leading order (LO) and next-to-leading order (NLO) contributions to inclusive photon production in proton-proton (p+p) collisions at the LHC. These channels provide the dominant contribution at LO and NLO for photon transverse momenta corresponding to momentum fractions of in the colliding protons. Our computations, performed in the dilute-dense framework of the Color Glass Condensate effective field theory (CGC EFT), show that the NLO contribution dominates at small- because it is sensitive to -dependent unintegrated gluon distributions in both of the protons. We predict a maximal modification of the cross section at low as a direct consequence of the violation of -factorization. The coherence effects responsible for this modification are enhanced in nuclei and can be identified from inclusive photon measurements in proton-nucleus collisions. We provide numerical results for the isolated inclusive photon cross section for GeV in p+p collisions that can be tested in the future at the LHC.

    ↳ hep-phnucl-exnucl-thPLB(2019)·41 citations
  2. 07

    The pseudogap regime in the unitary Fermi gas

    S. Jensen🇺🇸 · C. N. Gilbreth🇺🇸 · Y. Alhassid🇺🇸

    We discuss the pseudogap regime in the cold atomic unitary Fermi gas, with a particular emphasis on the auxiliary-field quantum Monte Carlo (AFMC) approach. We discuss possible signatures of the pseudogap, review experimental results, and survey analytic and quantum Monte Carlo techniques before focusing on AFMC calculations in the canonical ensemble. For the latter method, we discuss results for the heat capacity, energy-staggering pairing gap, spin susceptibility, and compare to experiment and other theoretical methods.

    ↳ cond-mat.quant-gascond-mat.supr-connucl-thEur.Phys.J.ST(2019)·17 citations
  4. 09

    Energy and system size dependence of subnucleonic fluctuations

    Heikki Mäntysaari🇫🇮 · Björn Schenke🇺🇸

    The energy evolution of the fluctuating proton structure is studied by solving the JIMWLK renormalization group equation. The initial condition at moderate is obtained by fitting the charm reduced cross section data from HERA, requiring that the proton size remains compatible with the diffractive vector meson production measurements. Additionally, we show that the nucleon shape fluctuations are visible in exclusive vector meson production off nuclei.

    ↳ hep-phnucl-thNPA(2019)·0 citations
  5. 10

    NNNLO pressure of cold quark matter: leading logarithm

    Tyler Gorda🇫🇮 · Aleksi Kurkela🇨🇭 · Paul Romatschke🇺🇸 · Saga Säppi🇫🇮 · Aleksi Vuorinen🇫🇮

    At high baryon chemical potential , the equation of state of QCD allows a weak-coupling expansion in the QCD coupling . The result is currently known up to and including the full next-to-next-to-leading order (NNLO) . Starting at this order, the computations are complicated by the modification of particle propagation in a dense medium, which necessitates non-perturbative treatment of the scale . In this work, we apply a Hard-Thermal-Loop scheme for capturing the contributions of this scale to the weak-coupling expansion, and use it to determine the leading-logarithm contribution to NNNLO: . This result is the first improvement to the equation of state of massless cold quark matter in 40 years. The new term is negligibly small, and thus significantly increases our confidence in the applicability of the weak-coupling expansion.

    ↳ hep-phastro-ph.HEnucl-thPRL(2018)·159 citations
  6. 11

    Lattice Improvement in Lattice Effective Field Theory

    Nico Klein🇩🇪 · Dean Lee🇺🇸 · Ulf-G. Meißner🇩🇪

    Lattice calculations using the framework of effective field theory have been applied to a wide range few-body and many-body systems. One of the challenges of these calculations is to remove systematic errors arising from the nonzero lattice spacing. Fortunately, the lattice improvement program pioneered by Symanzik provides a formalism for doing this. While lattice improvement has already been utilized in lattice effective field theory calculations, the effectiveness of the improvement program has not been systematically benchmarked. In this work we use lattice improvement to remove lattice errors for a one-dimensional system of bosons with zero-range interactions. We construct the improved lattice action up to next-to-next-to-leading order and verify that the remaining errors scale as the fourth power of the lattice spacing for observables involving as many as five particles. Our results provide a guide for increasing the accuracy of future calculations in lattice effective field theory with improved lattice actions.

    ↳ hep-latnucl-thphysics.atm-clusEPJA(2018)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE