Lattice QCD Determination of $g_A$
Lattice QCD Determination of $g_A$
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$g_A$ 的晶格 QCD 测定
DOI：
10.22323/1.317.0020
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
E. Rinaldi
中科院分区：
文献类型：
--
作者：
A. Walker;E. Berkowitz;D. Brantley;A. Gambhir;P. Vranas;C. Bouchard;Chia;M. Clark;N. Garron;B. Jo'o;T. Kurth;H. Monge;A. Nicholson;C. Monahan;K. Orginos;E. Rinaldi
核子轴向耦合，$g_A$，是质子和中子的一个基本性质，它决定了标准模型中弱轴向流与核子耦合的强度，从而决定了自由中子的寿命。g_A在核物理中的重要性使它成为一个基准量，用来校准核子结构的格点QCD计算和更复杂的一个或几个核子系统的电弱矩阵元的计算。在确定$g_A$方面存在许多重大挑战，特别是臭名昭著的指数差信噪比问题和对数十万随机样本的要求，这使得该目标比最初想象的更难以实现。
我将描述使用一种非传统的计算方法，加上“可笑的”快速GPU代码，访问公开可用的格QCD配置从MILC和访问领导计算，使这些挑战得以克服，导致确定$g_A$与1%的精度和所有来源的系统不确定性控制。我将讨论这些结果对SU（2）手征微扰理论收敛性的影响，以及进一步改进g_A（亚百分比精度，我们有初步结果）的前景，这是格点QCD在核物理中更全面应用的一部分。这是特别令人兴奋的，因为新的CORAL超级计算机即将上线，Sierra和Summit，我们的晶格QCD代码实现了机器对机器的速度超过泰坦一个数量级。
The nucleon axial coupling, $g_A$, is a fundamental property of protons and neutrons, dictating the strength with which the weak axial current of the Standard Model couples to nucleons, and hence, the lifetime of a free neutron. The prominence of $g_A$ in nuclear physics has made it a benchmark quantity with which to calibrate lattice QCD calculations of nucleon structure and more complex calculations of electroweak matrix elements in one and few nucleon systems. There were a number of significant challenges in determining $g_A$, notably the notorious exponentially-bad signal-to-noise problem and the requirement for hundreds of thousands of stochastic samples, that rendered this goal more difficult to obtain than originally thought.
I will describe the use of an unconventional computation method, coupled with "ludicrously'" fast GPU code, access to publicly available lattice QCD configurations from MILC and access to leadership computing that have allowed these challenges to be overcome resulting in a determination of $g_A$ with 1% precision and all sources of systematic uncertainty controlled. I will discuss the implications of these results for the convergence of $SU(2)$ Chiral Perturbation theory for nucleons, as well as prospects for further improvements to $g_A$ (sub-percent precision, for which we have preliminary results) which is part of a more comprehensive application of lattice QCD to nuclear physics. This is particularly exciting in light of the new CORAL supercomputers coming online, Sierra and Summit, for which our lattice QCD codes achieve a machine-to-machine speed up over Titan of an order of magnitude.
影响因子：
5
作者：
A. Chambers;R. Horsley;A. Schiller;H. Stüben;D. Pleiter;D. Pleiter;J. Zanotti;H. Perlt;Y. Nakamura;P. Rakow;G. Schierholz;R. Young
通讯作者：
A. Chambers;R. Horsley;A. Schiller;H. Stüben;D. Pleiter;D. Pleiter;J. Zanotti;H. Perlt;Y. Nakamura;P. Rakow;G. Schierholz;R. Young
影响因子：
5
作者：
E. Berkowitz;C. Bouchard;C. C. Chang-C.;M. A. Clark;-B.;Joo;T. Kurth;C. Monahan;A. Nicholson;K. Orginos;-E.;Rinaldi;P. Vranas;A. Walker-Loud
通讯作者：
E. Berkowitz;C. Bouchard;C. C. Chang-C.;M. A. Clark;-B.;Joo;T. Kurth;C. Monahan;A. Nicholson;K. Orginos;-E.;Rinaldi;P. Vranas;A. Walker-Loud
影响因子：
5
作者：
K. Nakamura;K. Hagiwara;K. Hikasa;H. Murayama;M. Tanabashi;T. Watari;C. Amsler;M. Antonelli
通讯作者：
K. Nakamura;K. Hagiwara;K. Hikasa;H. Murayama;M. Tanabashi;T. Watari;C. Amsler;M. Antonelli