Applications of Effective Theories of QCD in Collider Physics

In this thesis, we apply effective theories of Quantum Chromodynamics (QCD) in collider physics. First, we apply heavy quark effective theory (HQET) on the production asymmetries of heavy hadrons in collider experiments. Asymmetries of the partial widths of a heavy hadron and its antiparticle contain information about CP -violation. In collider experiments, Partial widths are inevitably entangled with production rates. Therefore, understanding production asymmetries is essential in extracting information about CP violation from collider experiments. At leading twist in perturbative QCD, such production asymmetries are absent. Using heavy quark effective theory (HQET), we examine the subleading-twist processes which can produce the productions asymmetries. By fitting several non-perturbative parameters to data, the production asymmetries of D+/D− measured at LHCb can be explained reasonably well. We also make predictions on production asymmetries of ΛQ/\bar ΛQ at the LHC. The asymmetries are found to be significant in the forward region and should be measurable by LHCb. In addition, for further investigation in the future, we compute the partonic cross sections for P waves. Second, we apply soft-collinear effective theory (SCET) to resum large logarithms ln(1 −m^2_VH/\hat s ) in the threshold region m^2_VH → \hat s for the associated production of the Higgs boson with a vector boson at the LHC. The effect of NNNLL resummation on the total cross section at NNLO is found to be negligible. For the distribution in τ = M^2_VH /s, the NNLL resummation increases the fixed-order NLO result by ∼ 10% at τ ∼ 0.1, suggesting the the importance of threshold resummation at τ of moderate size

Role of interleukin-13 on the development of minimal change nephrotic syndrome - A novel animal model

Ph.DDOCTOR OF PHILOSOPH

Spin structure of heavy-quark hybrids

A unique feature of quantum chromodynamics (QCD), the theory of strong interactions, is the possibility for gluonic degrees of freedom to participate in the construction of physical hadrons, which are color singlets, in an analogous manner to valence quarks. Hadrons with no valence quarks are called glueballs, while hadrons where both gluons and valence quarks combine to form a color singlet are called hybrids. The unambiguous identification of such states among the experimental hadron spectrum has been thus far not possible. Glueballs are particularly difficult to establish experimentally since the lowest lying ones are expected to strongly mix with conventional mesons. On the other hand, hybrids should be easier to single out because the set of quantum numbers available to their lowest excitations may be exotic, i.e., not realized in conventional quark-antiquark systems. Particularly promising for discovery appear to be heavy hybrids, which are made of gluons and a heavy-quark-antiquark pair (charm or bottom). In the heavy-quark sector systematic tools can be used that are not available in the light-quark sector. In this paper we use a nonrelativistic effective field theory to uncover for the first time the full spin structure of heavy-quark hybrids up to $1/m^2$-terms in the heavy-quark-mass expansion. We show that such terms display novel characteristics at variance with our consolidated experience on the fine and hyperfine splittings in atomic, molecular and nuclear physics. We determine the nonperturbative contributions to the matching coefficients of the effective field theory by fitting our results to lattice-QCD determinations of the charmonium hybrid spectrum and extrapolate the results to the bottomonium hybrid sector where lattice-QCD determinations are still challenging.Comment: 10 pages, 3 figures. Updated version including the corrections in the erratum of Journal version. Two additional operators included, figures and analysis update

Large Separable Kernel Attention: Rethinking the Large Kernel Attention Design in CNN

Visual Attention Networks (VAN) with Large Kernel Attention (LKA) modules have been shown to provide remarkable performance, that surpasses Vision Transformers (ViTs), on a range of vision-based tasks. However, the depth-wise convolutional layer in these LKA modules incurs a quadratic increase in the computational and memory footprints with increasing convolutional kernel size. To mitigate these problems and to enable the use of extremely large convolutional kernels in the attention modules of VAN, we propose a family of Large Separable Kernel Attention modules, termed LSKA. LSKA decomposes the 2D convolutional kernel of the depth-wise convolutional layer into cascaded horizontal and vertical 1-D kernels. In contrast to the standard LKA design, the proposed decomposition enables the direct use of the depth-wise convolutional layer with large kernels in the attention module, without requiring any extra blocks. We demonstrate that the proposed LSKA module in VAN can achieve comparable performance with the standard LKA module and incur lower computational complexity and memory footprints. We also find that the proposed LSKA design biases the VAN more toward the shape of the object than the texture with increasing kernel size. Additionally, we benchmark the robustness of the LKA and LSKA in VAN, ViTs, and the recent ConvNeXt on the five corrupted versions of the ImageNet dataset that are largely unexplored in the previous works. Our extensive experimental results show that the proposed LSKA module in VAN provides a significant reduction in computational complexity and memory footprints with increasing kernel size while outperforming ViTs, ConvNeXt, and providing similar performance compared to the LKA module in VAN on object recognition, object detection, semantic segmentation, and robustness tests

Development of teaching beliefs and the focus of change in the process of pre-service ESL teacher education

This study sets out to investigate how pre-serviceESLteachers shape their beliefs in the process of experimenting with new teaching methods introduced in the teacher education programme. A 4-year longitudinal study was conducted with four randomly selectedESLpre-service teachers. Their theoretical orientations ofESLinstruction were tracked at intervals through a protocol which consisted of i) descriptive accounts, ii) surveys, iii) lesson plan analysis, iv) lesson recording and v) interviews. Despite the fact that these 4 student teachers had shown different theoretical orientations in the protocols, they shared similar patterns of instructional practices in the Teaching Practicum. It was also found that the new teaching method practiced in the teacher education programme was re-conceptualised by these student teachers in the actual teaching context because of the strong influence of their personal agency beliefs