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8.0

Jun 28, 2018
06/18

by
K. U. Can; G. Erkol; M. Oka; T. T. Takahashi

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The electromagnetic form factors of the spin-3/2 $\Omega$ baryons, namely $\Omega$, $\Omega_c^\ast$, $\Omega_{cc}^\ast$ and $\Omega_{ccc}$, are calculated in full QCD on $32^3\times 64$ PACS-CS lattices with a pion mass of 156(9) MeV. The electric charge radii and magnetic moments from the $E0$ and $M1$ multipole form factors are extracted. Results for the electric quadrupole form factors, $E2$, are also given. Quark sector contributions are computed individually for each observable and then...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1508.03048

5
5.0

Jun 30, 2018
06/18

by
Constantia Alexandrou

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We review results on hadron structure using lattice QCD simulations with pion masses close or at to the physical value. We pay particular attention to recent successes on the computation of the mass of the low-lying baryons and on the challenges involved in evaluating energies of excited states and resonance parameters, as well as, in studies of nucleon structure.

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice, Nuclear Theory

Source: http://arxiv.org/abs/1411.3495

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31

Jun 29, 2018
06/18

by
Huey-Wen Lin

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We present a sampling of analyses concerning the gender ratio of plenary speakers during the years 2000--2016 and make comparisons with other conferences, such as the APS April meeting. We hope this will invite discussion of ideas for how to make our field more accessible to women and minorities. We are preparing for an in-depth survey of the lattice field and welcome any ideas or suggestions. To leave post-conference comments and read about news affecting women in our field, see our Facebook...

Topics: High Energy Physics - Lattice, Physics, Physics and Society

Source: http://arxiv.org/abs/1612.09367

3
3.0

Jun 29, 2018
06/18

by
Daniel August; Björn Wellegehausen; Andreas Wipf

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Albeit the standard model is the most successful model of particles physics, it still has some theoretical shortcomings, for instance the hierarchy problem, the absence of dark matter, etc. Supersymmetric extensions of the standard model could be a possible solution to these problems. One of the building blocks of these supersymmetric models are supersymmetric gauge theories. It is expected that they exhibit interesting features like confinement, chiral symmetry breaking, magnetic monopoles and...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1611.00551

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6.0

Jun 27, 2018
06/18

by
Yuya Tanizaki; Hiromichi Nishimura; Kouji Kashiwa

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The fermion sign problem appearing in the mean-field approximation is considered, and the systematic computational scheme of the free energy is devised by using the Lefschetz-thimble method. We show that the Lefschetz-thimble method respects the reflection symmetry, which makes physical quantities manifestly real at any order of approximations using complex saddle points. The formula is demonstrated through the Airy integral as an example, and its application to the Polyakov-loop effective...

Topics: High Energy Physics - Lattice, Condensed Matter, Strongly Correlated Electrons, Nuclear Theory,...

Source: http://arxiv.org/abs/1504.02979

7
7.0

Jun 28, 2018
06/18

by
Yuya Tanizaki; Yoshimasa Hidaka; Tomoya Hayata

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The Lefschetz-thimble approach to path integrals is applied to a one-site model of electrons, i.e., the one-site Hubbard model. Since the one-site Hubbard model shows a non-analytic behavior at the zero temperature and its path integral expression has the sign problem, this toy model is a good testing ground for an idea or a technique to attack the sign problem. Semiclassical analysis using complex saddle points unveils the significance of interference among multiple Lefschetz thimbles to...

Topics: High Energy Physics - Lattice, Strongly Correlated Electrons, Condensed Matter, High Energy Physics...

Source: http://arxiv.org/abs/1509.07146

5
5.0

Jun 30, 2018
06/18

by
Marjan-S. Mirahmadi; Amir H. Fatollahi; Mohammad Khorrami

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On a lattice, as the momentum space is compact, the kinetic energy is bounded not only from below but also from above. It is shown that this, somehow removes the distinction between repulsive and attractive forces. In particular, it is seen that a region with attractive force would appear forbidden for states with energies higher than a certain value, while repulsive forces could develop bound-states. An explicit transformation is introduced which transforms the spectrum of a system...

Topics: Quantum Physics, High Energy Physics - Theory, Mathematics, High Energy Physics - Lattice,...

Source: http://arxiv.org/abs/1405.4199

4
4.0

Jun 25, 2018
06/18

by
E. P. Politis; C. E. Tsagkarakis; F. K. Diakonos; X. N. Maintas; A. Tsapalis

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We propose a quasi-particle model for the thermodynamic description of the gluon plasma which takes into account non-abelian characteristics of the gluonic field. This is accomplished utilizing massive non-linear plane wave solutions of the classical equations of motion with a variable mass parameter, reflecting the scale invariance of the Yang-Mills Lagrangian. For the statistical description of the gluon plasma we interpret these non-linear waves as quasi-particles with a temperature...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice, Nuclear Theory

Source: http://arxiv.org/abs/1501.01032

6
6.0

Jun 25, 2018
06/18

by
Nigel Cundy; Weonjong Lee

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We discuss the usage and applicability of deflation methods for the overlap lattice Dirac operator, focussing on calculating the eigenvalues using a method similar to the eigCG algorithm used for other Dirac operators. The overlap operator, which contains several theoretical advantages over other formulations of lattice Quantum Chromodynamics, is more computationally expensive because it requires the computation of the matrix sign function. The principle change made compared to deflation...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1501.01855

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25

Jun 27, 2018
06/18

by
A. Francis; O. Kaczmarek; M. Laine; T. Neuhaus; H. Ohno

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We explore a method developed in statistical physics which has been argued to have exponentially small finite-volume effects, in order to determine the critical temperature Tc of pure SU(3) gauge theory close to the continuum limit. The method allows us to estimate the critical coupling betac of the Wilson action for temporal extents up to Nt ~ 20 with < 0.1% uncertainties. Making use of the scale setting parameters r0 and sqrt{t0} in the same range of beta-values, these results lead to the...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1503.05652

5
5.0

Jun 27, 2018
06/18

by
Georg Bergner; Jens Langelage; Owe Philipsen

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We consider a three-dimensional effective theory of Polyakov lines derived previously from lattice Yang-Mills theory and QCD by means of a resummed strong coupling expansion. The effective theory is useful for investigations of the phase structure, with a sign problem mild enough to allow simulations also at finite density. In this work we present a numerical method to determine improved values for the effective couplings directly from correlators of the 4d Yang-Mills theory. For values of the...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1505.01021

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10.0

Jun 28, 2018
06/18

by
Marco Cè; Cristian Consonni; Georg P. Engel; Leonardo Giusti

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We study the topological charge distribution of the SU(3) Yang--Mills theory with high precision in order to be able to detect deviations from Gaussianity. The computation is carried out on the lattice with high statistics Monte Carlo simulations by implementing a naive discretization of the topological charge evolved with the Yang--Mills gradient flow. This definition is far less demanding than the one suggested from Neuberger's fermions and, as shown in this paper, in the continuum limit its...

Topics: High Energy Physics - Lattice, High Energy Physics - Theory

Source: http://arxiv.org/abs/1506.06052

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12

Jun 28, 2018
06/18

by
S. A. Owerre

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We study the physics of quantum spin Hall (QSH) effect and topological quantum phase transition on the porphyrin lattice. We show that in a special limit the pristine model on this lattice reduces to the usual topological insulator (TI) thin film model. By incorporating explicit time reversal symmetry (TRS) breaking interactions, we explore the topological properties of this model and show that it exhibits an ordinary insulator phase, a quantum anomalous Hall (QAH) phase, and a quantum spin...

Topics: Quantum Physics, Mathematical Physics, Condensed Matter, High Energy Physics - Lattice,...

Source: http://arxiv.org/abs/1506.09204

4
4.0

Jun 30, 2018
06/18

by
Jonathan M. M. Hall; Waseem Kamleh; Derek B. Leinweber; Benjamin J. Menadue; Benjamin J. Owen; Anthony W. Thomas; Ross D. Young

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For almost 50 years the structure of the Lambda 1405 resonance has been a mystery. Recently, a new lattice QCD simulation showing that its strange magnetic form factor vanishes, together with a comprehensive Hamiltonian analysis of the lattice QCD energy levels, has unambiguously established that the structure is dominated by a bound anti-kaon--nucleon component [1]. Here we present supplementary information for Ref. [1] including a presentation of the relevant Hamiltonian effective field...

Topics: High Energy Physics - Lattice, Nuclear Theory

Source: http://arxiv.org/abs/1411.3781

8
8.0

Jun 27, 2018
06/18

by
Nikhil Karthik; Rajamani Narayanan

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We use canonical formalism to study the fermion determinant in different three dimensional abelian gauge field backgrounds that contain non-zero magnetic and electric flux in order to understand the non-perturbative contributions to the parity-odd and parity-even parts of the phase. We show that a certain phase associated with free fermion propagation along a closed path in a momentum torus is responsible for the parity anomaly in a background with non-zero electric flux. We consider...

Topics: High Energy Physics - Lattice, Strongly Correlated Electrons, Condensed Matter, High Energy Physics...

Source: http://arxiv.org/abs/1505.01051

5
5.0

Jun 25, 2018
06/18

by
Lei Wang; Mauro Iazzi; Philippe Corboz; Matthias Troyer

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We present the ground state extension of the efficient quantum Monte Carlo algorithm for lattice fermions of arXiv:1411.0683. Based on continuous-time expansion of imaginary-time projection operator, the algorithm is free of systematic error and scales \emph{linearly} with projection time and interaction strength. Compared to the conventional quantum Monte Carlo methods for lattice fermions, this approach has greater flexibility and is easier to combine with powerful machinery such as histogram...

Topics: Strongly Correlated Electrons, Condensed Matter, High Energy Physics - Lattice, Computational...

Source: http://arxiv.org/abs/1501.00986

7
7.0

Jun 27, 2018
06/18

by
Heechang Na; Chris M. Bouchard; G. Peter Lepage; Chris Monahan; Junko Shigemitsu

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We present a lattice QCD calculation of the $B \rightarrow D l \nu$ semileptonic decay form factors $f_+(q^2)$ and $f_0(q^2)$ for the entire physical $q^2$ range. Non-relativistic QCD (NRQCD) bottom quarks and Highly Improved Staggered Quark (HISQ) charm and light quarks are employed together with $N_f = 2+1$ MILC gauge configurations. A joint fit to our lattice and BaBar experimental data allows an extraction of the CKM matrix element $|V_{cb}|$. We also determine the phenomenologically...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1505.03925

6
6.0

Jun 30, 2018
06/18

by
M. Bruno; M. Dalla Brida; P. Fritzsch; T. Korzec; A. Ramos; S. Schaefer; H. Simma; S. Sint; R. Sommer

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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, $1/L_{\rm had}$. We then discuss how to determine this scale in...

Topics: High Energy Physics - Lattice, High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1701.03075

3
3.0

Jun 30, 2018
06/18

by
Jorge Segovia; Ian C. Cloet; Craig D. Roberts; Sebastian M. Schmidt

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We compute nucleon and Delta elastic and transition form factors, and compare predictions made using a framework built upon a Faddeev equation kernel and interaction vertices that possess QCD-like momentum dependence with results obtained using a vector-vector contact-interaction. The comparison emphasises that experiment is sensitive to the momentum dependence of the running couplings and masses in the strong interaction sector of the Standard Model and highlights that the key to describing...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice, Nuclear Experiment, Nuclear...

Source: http://arxiv.org/abs/1408.2919

3
3.0

Jun 26, 2018
06/18

by
Wolfgang Söldner; for the RQCD Collaboration

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Based on CLS simulations with 2+1 flavors and open boundaries we present first results of the baryon spectrum. We report on the status of our effort related to these simulations and the chiral extrapolation to the physical point.

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1502.05481

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7.0

Jun 28, 2018
06/18

by
Peter Boyle; Azusa Yamaguchi; Guido Cossu; Antonin Portelli

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In this proceedings we discuss the motivation, implementation details, and performance of a new physics code base called Grid. It is intended to be more performant, more general, but similar in spirit to QDP++\cite{QDP}. Our approach is to engineer the basic type system to be consistently fast, rather than bolt on a few optimised routines, and we are attempt to write all our optimised routines directly in the Grid framework. It is hoped this will deliver best known practice performance across...

Topics: Mathematical Software, High Energy Physics - Lattice, Distributed, Parallel, and Cluster Computing,...

Source: http://arxiv.org/abs/1512.03487

3
3.0

Jun 30, 2018
06/18

by
S. Simula

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Leptonic and semileptonic kaon decays represent till now the golden modes for the extraction of the Cabibbo angle from experiments, provided the relevant hadronic quantities, namely the ratio of the kaon and pion leptonic decay constants, $f_K / f_\pi$, and the semileptonic vector form factor at zero four-momentum transfer, $f_+(0)$, are computed accurately from QCD. In the last years, using large-scale lattice QCD simulations, the determination of both $f_K / f_\pi$ and $f_+(0)$ has reached an...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1704.00510

3
3.0

Jun 30, 2018
06/18

by
Jishnu Goswami; Dipankar Chakrabarti; Subhasish Basak

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Minimally doubled fermion proposed by Creutz and Borici is a promising chiral fermion formulation on lattice. In this work, we present excited state mass spectroscopy for the meson bound states in Gross-Neveu model using Borici-Creutz fermion. We also evaluate the effective fermion mass as a function of coupling constant which shows a chiral phase transition at strong coupling. The lowest lying meson in 2-dimensional QED is also obtained using Borici-Creutz fermion.

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1704.00925

3
3.0

Jun 30, 2018
06/18

by
A. J. Chambers; R. Horsley; Y. Nakamura; H. Perlt; D. Pleiter; P. E. L. Rakow; G. Schierholz; A. Schiller; H. Stüben; R. D. Young; J. M. Zanotti

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We perform a Nf = 2 + 1 lattice QCD simulation to determine the quark spin fractions of hadrons using the Feynman-Hellmann theorem. By introducing an external spin operator to the fermion action, the matrix elements relevant for quark spin fractions are extracted from the linear response of the hadron energies. Simulations indicate that the Feynman-Hellmann method offers statistical precision that is comparable to the standard three-point function approach, with the added benefit that it is...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1405.3019

4
4.0

Jun 30, 2018
06/18

by
Tatsuhiro Misumi; Takuya Kanazawa

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We investigate QCD with adjoint Dirac fermions on $\mathbb{R}^3\times S^1$ with generic boundary conditions for fermions along $S^1$. By means of perturbation theory, semiclassical methods and a chiral effective model, we elucidate a rich phase structure in the space spanned by the $S^1$ compactification scale $L$, twisted fermionic boundary condition $\phi$ and the fermion mass $m$. We found various phases with or without chiral and center symmetry breaking, separated by first- and...

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1405.3113

4
4.0

Jun 30, 2018
06/18

by
Raúl A. Briceño; Maxwell T. Hansen; André Walker-Loud

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We perform a model-independent, non-perturbative investigation of two-point and three-point finite-volume correlation functions in the energy regime where two-particle states can go on-shell. We study three-point functions involving a single incoming particle and an outgoing two-particle state, relevant, for example, for studies of meson decays (e.g., B-to-pi Kll) or meson photo production (e.g., pi gamma-to-pi pi). We observe that, while the spectrum solely depends on the on-shell scattering...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1406.5965

3
3.0

Jun 30, 2018
06/18

by
Seikou Kato; Kei-Ichi Kondo; Akihiro Shibata

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In the $SU(2)$ Yang-Mills theory on the four-dimensional Euclidean lattice, we confirm the gauge-independent "Abelian" dominance (or the restricted field dominance) and gauge-independent magnetic-monopole dominance in the string tension of the linear potential extracted from the Wilson loop in the fundamental representation. The dual Meissner effect is observed by demonstrating the squeezing of the chromoelectric field flux connecting a pair of quark and antiquark. In addition, the...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1407.2808

3
3.0

Jun 30, 2018
06/18

by
Masazumi Honda

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In theoretical physics, we sometimes have two perturbative expansions of physical quantity around different two points in parameter space. In terms of the two perturbative expansions, we introduce a new type of smooth interpolating function consistent with the both expansions, which includes the standard Pad\'e approximant and fractional power of polynomial method constructed by Sen as special cases. We point out that we can construct enormous number of such interpolating functions in principle...

Topics: High Energy Physics - Theory, Strongly Correlated Electrons, Mathematics, High Energy Physics -...

Source: http://arxiv.org/abs/1408.2960

2
2.0

Jun 30, 2018
06/18

by
Andrei Alexandru; Ivan Horváth

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We examine the feasibility of the proposition that there is a temperature range T$_c$ < T < T$_{ch}$ in N$_f$=0 QCD, where real Polyakov line (deconfined) vacuum exhibits valence spontaneous chiral symetry breaking and dynamical chiral polarization of Dirac eigenmodes. Detailed finite-volume analysis convincingly demonstrates the existence of such phase at fixed cutoff (a=0.085 fm). Moreover, it is found that this behavior also takes place closer to the continuum limit (a=0.060 fm)...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1409.7094

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4.0

Jun 30, 2018
06/18

by
Axel Cortés Cubero

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Yang Mills theory in 2+1 dimensions can be expressed as an array of coupled (1+1)-dimensional principal chiral sigma models. The $SU(N)\times SU(N)$ principal chiral sigma model in 1+1 dimensions is integrable, asymptotically free and has massive excitations. We calculate all the form factors and two-point correlation functions of the Noether current and energy-momentum tensor, in 't~Hooft's large-$N$ limit (some form factors can be found even at finite $N$). We use these new form factors to...

Topics: High Energy Physics - Theory, Nonlinear Sciences, Statistical Mechanics, Exactly Solvable and...

Source: http://arxiv.org/abs/1409.8341

2
2.0

Jun 30, 2018
06/18

by
Christian S. Fischer; Jan Lücker; Jan M. Pawlowski

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We investigate the nature of the deconfinement and Roberge-Weiss transition in the heavy quark regime for finite real and imaginary chemical potential within the functional approach to continuum QCD. We extract the critical phase boundary between the first order and cross-over regions, and also explore tricritical scaling. Our results confirm previous ones from finite volume lattice studies.

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1409.8462

3
3.0

Jun 30, 2018
06/18

by
Urs Gerber; Irais Bautista; Wolfgang Bietenholz; Héctor Mejía-Díaz; Christoph P. Hofmann

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In Monte Carlo simulations with a local update algorithm, the auto-correlation with respect to the topological charge tends to become very long. In the extreme case one can only perform reliable measurements within fixed sectors. We investigate approaches to extract physical information from such topologically frozen simulations. Recent results in a set of sigma-models and gauge theories are encouraging. In a suitable regime, the correct value of some observable can be evaluated to a good...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1410.0426

2
2.0

Jun 29, 2018
06/18

by
Andria Agadjanov; Véronique Bernard; Ulf-G. Meißner; Akaki Rusetsky

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The extraction of the $B\to K^*$ transition form factors from lattice data is studied, applying non-relativistic effective field theory in a finite volume. The possible mixing of $\pi K$ and $\eta K$ states is taken into account. The two-channel analogue of the Lellouch-L\"uscher formula is reproduced. Due to the resonance nature of the $K^*$, an equation is derived, which allows to determine the form factors at the pole position in a process-independent manner. The infinitely-narrow width...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1605.03386

2
2.0

Jun 29, 2018
06/18

by
Aleksey Cherman; Erich Poppitz

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$\mathcal{N}=1$ $SU(N)$ super-Yang-Mills theory on $\mathbb{R}^3\times S^1$ is believed to have a smooth dependence on the circle size $L$. Making $L$ small leads to calculable non-perturbative color confinement, mass gap, and string tensions. For finite $N$, the small-$L$ low-energy dynamics is described by a three-dimensional effective theory. The large-$N$ limit, however, reveals surprises: the infrared dual description is in terms of a theory with an emergent fourth dimension, curiously...

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1606.01902

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3.0

Jun 29, 2018
06/18

by
Fabrizio Canfora; Alex Giacomini; Pablo Pais; Luigi Rosa; Alfonso Zerwekh

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In this paper the compatibility is analyzed of the non-perturbative equations of state of quarks and gluons arising from the lattice with some natural requirements for self-gravitating objects at equilibrium: the existence of an equation of state (namely, the possibility to define the pressure as a function of the energy density), the absence of superluminal propagation and Le Chatelier's principle. It is discussed under which conditions it is possible to extract an equation of state (in the...

Topics: High Energy Physics - Theory, Astrophysics, High Energy Astrophysical Phenomena, High Energy...

Source: http://arxiv.org/abs/1606.02271

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2.0

Jun 29, 2018
06/18

by
Hua-Xing Chen; Er-Liang Cui; Wei Chen; Xiang Liu; Shi-Lin Zhu

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We investigate the newly observed $X(4500)$ and $X(4700)$ based on the diquark-antidiquark configuration within the framework of QCD sum rules. Both of them may be interpreted as the $D$-wave $cs\bar{c}\bar{s}$ tetraquark states of $J^P = 0^+$, but with opposite color structures, which is remarkably similar to the result obtained in Ref.~\cite{Chen:2010ze} that the $X(4140)$ and $X(4274)$ can be both interpreted as the $S$-wave $cs\bar{c}\bar{s}$ tetraquark states of $J^P = 1^+$, also with...

Topics: High Energy Physics - Phenomenology, Nuclear Experiment, High Energy Physics - Lattice, High Energy...

Source: http://arxiv.org/abs/1606.03179

2
2.0

Jun 29, 2018
06/18

by
M. Ruggieri; G. X. Peng; M. Chernodub

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We study microscopic processes responsible for chirality flips in the thermal bath of Quantum Chromodynamics at finite temperature and zero baryon chemical potential. We focus on the temperature range where the crossover from chirally broken phase to quark-gluon plasma takes place, namely $T \simeq (150, 200)$ MeV. The processes we consider are quark-quark scatterings mediated by collective excitations with the quantum number of pions and $\sigma$-meson, hence we refer to these processes simply...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice, Nuclear Theory

Source: http://arxiv.org/abs/1606.03287

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2.0

Jun 29, 2018
06/18

by
Rudy Arthur; Vincent Drach; Ari Hietanen; Claudio Pica; Francesco Sannino

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We investigate the scalar and pseudoscalar spectrum of the $SU(2)$ gauge theory with $N_f=2$ flavours of fermions in the fundamental representation using non perturbative lattice simulations. We provide first benchmark estimates of the mass of the lightest $0(0^{+})$ ($\sigma$), $0(0^{-})$ ($\eta'$) and $1(0^+)$ ($a_0$) states, including estimates of the relevant disconnected contributions. We find $m_{a_0}/F_{\rm{PS}}= 16.7(4.9)$, $m_\sigma/F_{\rm{PS}}=19.2(10.8)$ and $m_{\eta'}/F_{\rm{PS}} =...

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1607.06654

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2.0

Jun 29, 2018
06/18

by
Claudio Bonati; Massimo D'Elia; Paolo Rossi; Ettore Vicari

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We study the large-$N$ scaling behavior of the $\theta$ dependence of the ground-state energy density $E(\theta)$ of four-dimensional (4D) $SU(N)$ gauge theories and two-dimensional (2D) $CP^{N-1}$ models, where $\theta$ is the parameter associated with the Lagrangian topological term. We consider its $\theta$ expansion around $\theta=0$, $E(\theta)-E(0) = {1\over 2}\chi \,\theta^2 ( 1 + b_2 \theta^2 + b_4\theta^4 +\cdots)$ where $\chi$ is the topological susceptibility and $b_{2n}$ are...

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1607.06360

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2.0

Jun 29, 2018
06/18

by
Antoine Gérardin; Harvey B. Meyer; Andreas Nyffeler

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We calculate the $\pi^0\to \gamma^*\gamma^*$ transition form factor ${\cal F}_{\pi^0\gamma^*\gamma^*}(q_1^2,q_2^2)$ in lattice QCD with two flavors of quarks. Our main motivation is to provide the input to calculate the $\pi^0$-pole contribution to hadronic light-by-light scattering in the muon $(g-2)$, $a_\mu^{\rm HLbL;\pi^0}$. We therefore focus on the region where both photons are spacelike up to virtualities of about $1.5~$GeV$^2$, which has so far not been experimentally accessible....

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1607.08174

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2.0

Jun 29, 2018
06/18

by
Abdel Nasser Tawfik; Abdel Magied Diab; T. M. Hussein

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Due to off-center relativistic motion of the charged spectators and the local momentum-imbalance of the participants, a short-lived huge magnetic field is likely generated, especially in relativistic heavy-ion collisions. In determining the temperature dependence of bulk and shear viscosities of the QCD matter in vanishing and finite magnetic field, we utilize mean field approximation to the SU($3$) Polyakov linear-sigma model (PLSM). We compare between the results from two different...

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1608.01034

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3.0

Jun 29, 2018
06/18

by
Pedro Bicudo; Nuno Cardoso; Marco Cardoso

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We show the flux tubes produced by static quark-antiquark, quark-quark and quark-gluon charges at finite temperature. The sources are placed in the lattice with fundamental and adjoint Polyakov loops. We compute the square densities of the chromomagnetic and chromoelectric fields above and below the phase transition. Our results are gauge invariant and produced in pure gauge SU(3). The codes are written in CUDA and the computations are performed with GPUs.

Topic: High Energy Physics - Lattice

Source: http://arxiv.org/abs/1608.07742

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2.0

Jun 29, 2018
06/18

by
Tin Sulejmanpasic; Mithat Ünsal

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We discuss a general setup which allows the study of the perturbation theory of an arbitrary, locally harmonic 1D quantum mechanical potential as well as its multi-variable (many-body) generalization. The latter may form a prototype for regularized quantum field theory. We first generalize the method of Bender-Wu, and derive exact recursion relations which allow the determination of the perturbative wave-function and energy corrections to an arbitrary order, at least in principle. For 1D...

Topics: High Energy Physics - Theory, Quantum Physics, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1608.08256

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3.0

Jun 29, 2018
06/18

by
M. N. Chernodub; V. A. Goy; A. V. Molochkov

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We propose a general numerical method to study the Casimir effect in lattice gauge theories. We illustrate the method by calculating the energy density of zero-point fluctuations around two parallel wires of finite static permittivity in Abelian gauge theory in two spatial dimensions. We discuss various subtle issues related to the lattice formulation of the problem and show how they can successfully be resolved. Finally, we calculate the Casimir potential between the wires of a fixed...

Topics: Statistical Mechanics, High Energy Physics - Lattice, Condensed Matter, Quantum Physics

Source: http://arxiv.org/abs/1609.02323

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2.0

Jun 29, 2018
06/18

by
Sasa Prelovsek

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Lattice QCD approach to study the hadronic resonances and exotic hadrons is described at an introductory level. The main challenge is that these states decay strongly via one or more decay channels, and they often lie near thersholds. Specific results for conventional and exotic hadrons are shown to illustrate the current status.

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1609.03052

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3.0

Jun 29, 2018
06/18

by
Nils Asmussen; Jeremy Green; Harvey B. Meyer; Andreas Nyffeler

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The anomalous magnetic moment of the muon currently exhibits a discrepancy of about three standard deviations between the experimental value and recent Standard Model predictions. The theoretical uncertainty is dominated by the hadronic vacuum polarization and the hadronic light-by-light (HLbL) scattering contributions, where the latter has so far only been fully evaluated using different models. To pave the way for a lattice calculation of HLbL, we present an expression for the HLbL...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1609.08454

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2.0

Jun 29, 2018
06/18

by
Mitsuhiro Kato; Makoto Sakamoto; Hiroto So

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N=4 supersymmetric quantum mechanical model is formulated on the lattice. Two supercharges, among four, are exactly conserved with the help of the cyclic Leibniz rule without spoiling the locality. In use of the cohomological argument, any possible local terms of the effective action are classified into two categories which we call type-I and type-II, analogous to the D- and F-terms in the supersymmetric field theories. We prove non-renormalization theorem on the type-II terms which include...

Topics: High Energy Physics - Theory, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1609.08793

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3.0

Jun 29, 2018
06/18

by
S. Prelovsek; U. Skerbis; C. B. Lang

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Operators for simulating the scattering of two particles with spin are constructed. Three methods are shown to give the consistent lattice operators for PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar meson, vector meson and nucleon. The projection method leads to one or several operators $O_{\Gamma,r,n}$ that transform according to a given irreducible representation $\Gamma$ and row r. However, it gives little guidance on which continuum quantum numbers of total J, spin S,...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1610.01126

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4.0

Jun 29, 2018
06/18

by
Gilberto Colangelo; Stefan Lanz; Heinrich Leutwyler; Emilie Passemar

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The $\eta \to 3 \pi$ amplitude is sensitive to the quark mass difference $m_u-m_d$ and offers a unique way to determine the quark mass ratio $Q^2 \equiv (m_s^2-m_{ud}^2)/(m_d^2-m_u^2)$ from experiment. We calculate the amplitude dispersively and fit the KLOE data on the charged mode, varying the subtraction constants in the range allowed by chiral perturbation theory. The parameter-free predictions obtained for the neutral Dalitz plot and the neutral-to-charged branching ratio are in excellent...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice, High Energy Physics - Experiment

Source: http://arxiv.org/abs/1610.03494

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2.0

Jun 29, 2018
06/18

by
Tuomas Lappi; Jarkko Peuron

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Classical lattice Yang-Mills calculations provide a good way to understand different nonequilibrium phenomena in nonperturbatively overoccupied systems. Above the Debye scale the classical theory can be matched smoothly to kinetic theory. The aim of this work is to study the limits of this quasiparticle picture by determining the plasmon mass in classical real time Yang-Mills theory on a lattice in 3 spatial dimensions. We compare three methods to determine the plasmon mass: a hard thermal loop...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice, Nuclear Theory

Source: http://arxiv.org/abs/1610.03711