# TH Articles

2017-01-20
07:22
 The $\Lambda$-parameter in 3-flavour QCD and $\alpha_s(m_Z)$ by the ALPHA collaboration / Bruno, M. (Brookhaven) ; Dalla Brida, M. (INFN, Milan Bicocca ; NIC, Zeuthen) ; Fritzsch, P. (CERN ; Madrid, IFT) ; Korzec, T. (Bergische U., Wuppertal (main)) ; Ramos, A. (CERN) ; Schaefer, S. (NIC, Zeuthen) ; Simma, H. (NIC, Zeuthen) ; Sint, S. (Trinity Coll., Dublin) ; Sommer, R. (NIC, Zeuthen ; Humboldt U., Berlin) We present results by the ALPHA collaboration for the $\Lambda$-parameter in 3-flavour QCD and the strong coupling constant at the electroweak scale, $\alpha_s(m_Z)$, in terms of hadronic quantities computed on the CLS gauge configurations. The first part of this proceedings contribution contains a review of published material \cite{Brida:2016flw,DallaBrida:2016kgh} and yields the $\Lambda$-parameter in units of a low energy scale, $1/L_{\rm had}$. [...] CERN-TH-2016-262; DESY-17-007; arXiv:1701.03075.- 2017-01-11 - 21 p. - Published in : PoS: LATTICE2016 (2016) , pp. 197 Fulltext: PDF;

2017-01-20
07:22
 Non-gaussianity of the critical 3d Ising model / Rychkov, Slava (CERN ; Ecole Normale Superieure ; UPMC, Paris (main)) ; Simmons-Duffin, David (Princeton, Inst. Advanced Study ; Caltech) ; Zan, Bernardo (ITPP, Lausanne ; CERN) We discuss the 4pt function of the critical 3d Ising model, extracted from recent conformal bootstrap results. We focus on the non-gaussianity Q - the ratio of the 4pt function to its gaussian part given by three Wick contractions. [...] CERN-TH-2016-249; CERN-PH-TH-2016-249; arXiv:1612.02436.- 2017 - 10 p. - Published in : SciPost Phys. 2 (2017) 001 Fulltext: pdf - PDF; arXiv:1612.02436 - PDF; SciPost Foundation Open Access article: PDF;

2016-11-01
07:47
 Massless Interacting Scalar Fields in de Sitter space / Nacir, Diana López (CERN) ; Mazzitelli, Francisco D (Balseiro Inst., San Carlos de Bariloche) ; Trombetta, Leonardo G (Balseiro Inst., San Carlos de Bariloche) We present a method to compute the two-point functions for an $O(N)$ scalar field model in de Sitter spacetime, avoiding the well known infrared problems for massless fields. The method is based on an exact treatment of the Euclidean zero modes and a perturbative one of the nonzero modes, and involves a partial resummation of the leading secular terms. [...] arXiv:1610.09943; CERN-TH-2016-151.- 2016 - 8 p. - Published in : EPJ Web Conf. 125 (2016) 05019 Preprint: PDF; External link: Preprint

2016-10-28
07:41
 D = 3 Unification of Curious Supergravities / Duff, M.J. (Imperial Coll., London ; Oxford U., Inst. Math.) ; Ferrara, S. (CERN ; INFN, Italy ; UCLA) ; Marrani, A. (Enrico Fermi Ctr., Rome ; INFN, Padua ; CERN ; Padua U.) We consider the dimensional reduction to D = 3 of four maximal-rank supergravities which preserve minimal supersymmetry in D = 11, 7, 5 and 4. Such "curious" theories were investigated some time ago, and the four-dimensional one corresponds to an N = 1 supergravity with 7 chiral multiplets spanning the seven-disk manifold. [...] arXiv:1610.08800; IMPERIAL-TP-2016-MJD-3; CERN-TH-2016-225; DFPD-2016-TH-18.- 2017 - 1+7 p. - Published in : J. High Energy Phys. 01 (2017) 023 Fulltext: PDF;

2016-10-24
07:21
 Exact $\nabla^4 R^4$ couplings and helicity supertraces / Bossard, Guillaume (Ecole Polytechnique, CPHT) ; Pioline, Boris (CERN ; Paris, LPTHE) In type II string theory compactified on a $d$-dimensional torus $T^d$ down to $D=10-d$ dimensions, the $R^4$ and $\nabla^4 R^4$ four-graviton couplings are known exactly, for all values of the moduli, in terms of certain Eisenstein series of the U-duality group $E_{d}(\mathbb{Z})$. In the limit where one circle in the torus becomes large, these couplings are expected to reduce to their counterpart in dimension $D+1$, plus threshold effects and exponentially suppressed corrections corresponding to BPS black holes in dimension $D+1$ whose worldline winds around the circle. [...] arXiv:1610.06693; CERN-TH-2016-224; CPHT-RR046.102016.- 2017 - 40 p. - Published in : J. High Energy Phys. 01 (2017) 050 Fulltext: PDF;

2016-10-22
07:28

2016-10-20
08:40
 Towards an automated tool to evaluate the impact of the nuclear modification of the gluon density on quarkonium, D and B meson production in proton-nucleus collisions / Lansberg, Jean-Philippe (Orsay, IPN) ; Shao, Hua-Sheng (CERN) We propose a simple and model-independent procedure to account for the impact of the nuclear modification of the gluon density as encoded in nuclear collinear PDF sets on two-to-two partonic hard processes in proton-nucleus collisions. This applies to a good approximation to quarkonium, D and B meson production, generically referred to H. [...] arXiv:1610.05382; CERN-TH-2016-206.- 2017 - 18 p. - Published in : Eur. Phys. J. C 77 (2017) 1 Fulltext: PDF;

2016-10-14
07:50
 Seven-Disk Manifold, alpha-attractors and B-modes / Ferrara, Sergio (CERN ; Frascati ; UCLA) ; Kallosh, Renata (Stanford U., ITP ; Stanford U., Phys. Dept.) Cosmological alpha-attractor models in \cN=1 supergravity are based on hyperbolic geometry of a Poincar\'e disk with the radius square {\cal R}^2=3\alpha. The predictions for the B-modes, r\approx 3\alpha {4\over N^2}, depend on moduli space geometry and are robust for a rather general class of potentials. [...] arXiv:1610.04163; CERN-TH-2016-214.- 2016 - 7. - Published in : Phys. Rev. D 94 (2016) 126015 APS Open Access article: PDF; Fulltext: PDF; External link: Preprint

2016-10-13
08:17
 Six-dimensional Origin of $\mathcal{N}=4$ SYM with Duality Defects / Assel, Benjamin (CERN ; King's Coll. London, Dept. Math) ; Schäfer-Nameki, Sakura (Oxford U., Inst. Math. ; King's Coll. London, Dept. Math) We study the topologically twisted compactification of the 6d $(2,0)$ M5-brane theory on an elliptically fibered K\"ahler three-fold preserving two supercharges. We show that upon reducing on the elliptic fiber, the 4d theory is $\mathcal{N}=4$ Super-Yang Mills, with varying complexified coupling $\tau$, in the presence of defects. [...] arXiv:1610.03663; CERN-TH-2016-216.- 2016 - 62 p. - Published in : J. High Energy Phys. 12 (2016) 058 Fulltext: PDF; Springer Open Access article: PDF;

2016-10-08
07:49
 Time evolution of linearized gauge field fluctuations on a real-time lattice / Kurkela, Aleksi (CERN ; Stavanger U.) ; Lappi, Tuomas (Jyvaskyla U. ; Helsinki Inst. of Phys.) ; Peuron, Jarkko (Jyvaskyla U.) Classical real-time lattice simulations play an important role in understanding non-equilibrium phenomena in gauge theories and are used in particular to model the prethermal evolution of heavy-ion collisions. Due to instabilities, small quantum fluctuations on top of the classical background may significantly affect the dynamics of the system. [...] arXiv:1610.01355; CERN-TH-2016-208.- 2016 - 8 p. - Published in : Eur. Phys. J. C 76 (2016) 688 Fulltext: PDF; Springer Open Access article: PDF;