We present a systematic formalism based on a factorization theorem in soft-collinear effective theory to describe non-global observables at hadron colliders, such as gap-between-jets cross sections. The cross sections are factorized into convolutions of hard functions, capturing the dependence on the partonic center-of-mass energy, and low-energy matrix elements, which are sensitive to the low...
We calculated partial SM NLO electroweak corrections to Higgs pair production in gluon fusion, which are proportional to triple Higgs self-interacting constant. Then we did the same calculations with the Standard Model Effective Field Theory (SMEFT) dimension-6 Higgs self-interacting operators, and calculated the cross sections corresponding to different SMEFT parameters.
In this talk we will discuss the recent processes in the calculation of the high-order perturbative corrections to the semi-inclusive production and decay of top quarks at lepton colliders at N3LO in QCD. In particular, the talk will be focusing on the first high-precision calculation of the complete QCD corrections to the top-quark decay width $\Gamma_t$, $W$-helicity fractions and...
The resummation calculation (ResBos) is a widely used tool for the simulation of single vector boson production at colliders. As the improvement over the ResBos code by increasing the accuracy from NNLL+NLO to N$^3$LL+NNLO, the nonperturbative function needs to be updated. We propose a new non-perturbative function (IFY) that includes information about the rapidity of the system. The IFY...
We present a first lattice QCD calculation of the transverse-momentum-dependent wave functions (TMDWFs) of the pion using large-momentum effective theory. Numerical simulations are based on one ensemble with 2+1+1 flavors of highly improved staggered quarks action with lattice spacing a = 0.121 fm from the MILC Collaboration, and one with 2 +1 flavor clover fermions and tree-level Symanzik...
We calculate the total cross-section and differential distributions of Higgs boson pair production and decay to $b \bar{b}\gamma \gamma$ at NLO in QCD.
We study the feasibility of observing sterile neutrino at the high energy colliders, using direct and indirect production channels in heavy meson/baryon and Higgs decays. It is found that these processes may set certain new constraints on the mass of sterile netrino in present running and next generation experiments.
The physics beyond the Standard Model (BSM) could be represented by a hidden sector at relatively low energy scales MeV-GeV and feeble couplings to SM. Their presence in our Universe would be revealed through indirect evidences such as small oscillations of SM parameters, cosmological and astrophysical considerations, and the complementary searches in accelerators. Here, I give an overview of...
Precision prediction for top quark physics
Top quark is the heaviest particle in the standard model. Once produced, the top quark immediately decays to a W boson and a bottom quark before hadronization. Precision studies for top quark physic plays essential role in the validity of the Standard Model and exploring potential avenues for new physics. In this talk I will review recently...
In view of both the latest LHCb measurement of $R_{K^{(*)}}$ and the new $2.8\sigma$ deviation reported by Belle II on $B^{+}\to K^{+}\nu\bar{\nu}$ decays, we present a fit to the $B$ meson anomalies for various one and two dimensional hypothesis including complex Wilson coefficients. We show in a model-independent way that the generic non-universal $U(1)^{\prime}$ extensions of the SM,...
In this talk, we explore the potential of probing the inelastic dark matter (DM) model with an extra $U(1)_D$ gauge symmetry at the Large Hadron Collider, ForwArd Search ExpeRiment and Super Tau Charm Factory. To saturate the observed DM relic density, the mass splitting between two light dark states has to be small enough, and thus leads to some distinctive signatures at these colliders. By...
The Higgs boson pair production via gluon-gluon fusion and vector boson fusion in the bbμμ final state at the LHC is studied to probe the Higgs self-coupling κλ and the four-boson HHVV coupling κ2V for the first time. A cut-based analysis and a machine-learning analysis using boosted decision trees are performed with categorizations and optimizations depending on the variations of these...
The longitudinal spin transfer represents the probability density of producing longitudinally polarized hadrons from longitudinally polarized quarks or circularly polarized gluons. It thus was usually measured in polarized reactions or high-energy collisions where weak interaction dominates. In this work, we propose the dihadron polarization correlation as a novel probe of this quantity. Such...
We present the first analytic results of N3LO QCD corrections to the top-quark decay width. We focus on the dominant leading color contribution, which includes light-quark loops. At NNLO, this dominant contribution accounts for 95% of the total correction. The most precise prediction for the top-quark width is now 1.321 GeV for mt = 172.69 GeV.
To probe new physics without prior assumptions on UV models, the correlation of operators could be crucial in exposing the structure of UV completion.
When operators arise from the same heavy resonance, they are likely to correlate and their Wilson coefficients exhibit non-trivial relation, since both of them depend on the same UV parameters.
The aim of EFT analysis is to discover the...
By tagging one or two intact protons in the forward direction, it is possible to select and measure exclusive photon-fusion processes at the LHC. The same processes can also be measured in heavy ion collisions, and are often denoted as ultraperipheral collisions (UPC) processes. Such measurements opens up the possibility to probe certain dimension-8 operators and their positivity bounds at...
We organize massive tree-level amplitudes in Standard Model by power counting and helicity category, and match them with their high energy origins. The construction of massive amplitudes is based on the massive bootstrap method, decomposing internal and external structures, and the existing leading orders of massless-massive correspondence. For the matching of higher order components, we...
It was found that, using nonrelativistic QCD factorization, the predicted $\chi_{cJ}$ hadroproduction cross section at large $p_T$ can be negative. The negative cross sections originate from terms proportional to plus function in ${^{3}\hspace{-0.6mm}P_{J}^{[1]}}$ channels, which are remnants of the infrared subtraction in matching the ${^{3}\hspace{-0.6mm}P_{J}^{[1]}}$ short-distance...
I will talk about the roles of LHC and low-energy (high-precision) experiments in searching for new physics at the TeV scale by studying the properties and interactions of neutrinos.
