AdS/QCD holographic light-front wavefunction, diffractive vector meson production and B physics

AdS/QCD 全息光前波函数、衍射矢量介子产生和 B 物理

• 批准号: SAPIN-2017-00033
• 负责人: Ahmady, Mohammad
• 金额: $ 1.46万
• 依托单位: Mount Allison University
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=677061
• 关键词: AdS; QCD; holographic; light; front

The discovery of Higgs boson by LHC in 2012 was an important step in validating the Standard Model (SM). However, there are already tensions between certain data and theoretical calculations based on SM. To make definite conclusions from these tensions, we need to improve the accuracy of both the measurement data and theoretical calculations. With the increase in luminosity and energy LHCb Run II (2015-19) expects to, at least, quadruple its effective statistics with the data collected until 2019 and hence half the uncertainties on the current measurements. In addition, SuperKEKB, which is an upgrade project of KEKB (1998-2010) at KEK (Japan) is designed to increase the instantaneous luminosity by about a factor of 40. Along with the BELLE II detector, this next-generation B-factory will complement the exploration of New Physics beyond the Standard Model currently being carried out at the energy frontier by LHC. The physics run of SuperKEKB will start in 2017. The numerous decay channels of the B mesons (quark-antiquark bound state containing a b-quark) to light mesons (quark-antiquark bound state with no b-quark) offer the opportunity to make precision tests of the Standard Model and perhaps more interestingly, to look for signals of physics beyond the SM. Exclusive B decays to light mesons are appealing since they are relatively easy to access experimentally, especially in an environment like the LHC. On the other hand, the theory of such decays is challenging due to the strong interactions effects. The theory of strong interactions, which is called quantum chromodynamics (QCD), becomes complicated when dealing with bound-state quantities. The computation of these quantities is challenging and model-dependent. Therefore, it is very important to make SM predictions using alternative viable approaches to nonperturbative QCD. ***In this research, we focus on increasing the reliability of our theoretical predictions for the exclusive B decays on both the perturbative and non-perturbative sides. First, we use an alternative and complimentary method to model QCD bound state effects. This method is known as light-front holography (LFH) and can be used to compute the non-perturbative inputs in theoretical calculations. Second, we are apply the so-called Principle of Maximum Conformality (PMC) to reduce the scale dependence of our theoretical predictions. ***We also plan to investigate the underlying connection between LFH and chiral perturbation theory which is another successful model for describing nonperturbative QCD. One should be able to deduce this connection by matching their predictions for the same physical quantity at a common kinematical range where both models are expected to be valid.

LHC在2012年发现Higgs Boson是验证标准模型（SM）的重要步骤。 但是，基于SM的某些数据和理论计算之间已经存在紧张关系。 为了从这些紧张局势中得出明确的结论，我们需要提高测量数据和理论计算的准确性。随着发光度和能源LHCB Run II（2015-19）的增加，至少可以将其有效统计数据与收集到2019年的数据进行四倍，因此一半的不确定性在当前的测量结果上。此外，SuperKekb是Kek（日本）Kekb（1998-2010）的升级项目，旨在将瞬时发光度提高约40倍。与Belle II探测器一起，这种下一代B因子将补充当前在Entractier Frontier by LHC上携带的标准模型以外的新物理学的探索。 Superkekb的物理运行将于2017年开始。B介子的众多衰减频道（Quark-Antiquark界面状态，包含B Quark），可轻而易举地使用Mesons（Quark-Antiquark Bound State，没有B QUARK）提供了机会，可以使标准模型的精确测试更加有趣，也许更有趣的是，以寻求SM sm smsics的信号。 b对介子的独家b衰变很有吸引力，因为它们相对容易实验，尤其是在LHC之类的环境中。另一方面，由于强烈的相互作用影响，这种衰减的理论具有挑战性。在处理界限时，强烈相互作用的理论被称为量子染色体动力学（QCD）变得复杂。 这些数量的计算具有挑战性和依赖模型。因此，使用替代性可行的QCD进行SM预测非常重要。 ***在这项研究中，我们专注于提高对扰动和非扰动方面的专有B衰减的理论预测的可靠性。首先，我们使用另一种和免费的方法来对QCD结合状态效应进行建模。该方法称为轻型全息图（LFH），可用于计算理论计算中的非扰动输入。其次，我们将应用所谓的最大形式保态原理（PMC）来减少我们理论预测的规模依赖性。 ***我们还计划研究LFH与手性扰动理论之间的潜在联系，这是描述非扰动QCD的另一个成功模型。 人们应该能够通过在公共运动范围内对相同物理数量的预测进行匹配，从而推断出这种连接，这两个模型都应有效。