We discuss kinematic methods for determining the masses of the particles in events at a hadron collider in which a pair of identical particles is produced with each decaying via a series of on-shell intermediate beyond-the-SM (BSM) particles to visible SM particles and an invisible particle (schematically, pp -> ZZ + jets with Z -> Aa -> Bba -> Ccba -> ... -> cba... + N where a,b,c,... are visible SM particles or groups of SM particles, A,B,C,... are on-shell BSM particles and N is invisible). This topology arises in many models including SUSY processes such as squark and gluino pair production and decay. We present the detailed procedure for the case of Z -> 3 visible particles + N and demonstrate that the masses obtained from the kinematic procedure are independent of the model by comparing SUSY to UED.
We present a new procedure to determine Parton Distribution Functions (PDFs), based on Markov Chain Monte Carlo (MCMC) methods. The aim of this paper is to show that we can replace the standard $χ^2$ minimization by procedures grounded on Statistical Methods, and on Bayesian inference in particular, thus offering additional insight into the rich field of PDFs determination. After a basic introduction to these technics, we introduce the algorithm we have chosen to implement -- namely Hybrid (or Hamiltonian) Monte Carlo. This algorithm, initially developed for Lattice QCD, turns out to be very i…
Determination of Nuclear PDFs using Markov Chain Monte Carlo Methods
Institute of Nuclear Physics Polish Academy of Sciences（波兰科学院核物理研究所）；Southern Methodist University（南方卫理公会大学）；Jefferson Lab（杰斐逊实验室）；Westfälische Wilhelms-Universität Münster（明斯特西法利亚威廉大学）
Determination of proton PDF uncertainties with Markov chain Monte Carlo
Institut für Theoretische Physik, Universität Münster（明斯特大学理论物理研究所）；Department of Physics, Southern Methodist University（南方卫理公会大学物理系）；Theory Center, Jefferson Lab（杰弗逊实验室理论中心）；Institute of Nuclear Physics Polish Academy of Sciences（波兰科学院核物理研究所）
Two jets and missing $E_T$ signature to determine the spins of the new particles
我们考虑了LHC早期能量加喷流通道中新有色粒子的自旋决定。我们用一个三位驼鹿模型来描述所有相同自旋伙伴（LHT或UED类）模型的低能拉格朗日量，并检验振幅的规范不变性。与超对称模型相比，在基准产生和衰变通道$pp \rightarrow U^{(R)} U^{(R)} \rightarrow u u B_H B_H$中，存在自旋关联，它影响了重伙伴$U^{(R)}$衰变产生的夸克的极角和方位角分布.我们表明，这种影响将是可见的$E_{\rm T miss} / M_{\rm eff}$分布和重建的方位角相关使用MAOS重建。
We consider SUSY-like events with two decay chains, each terminating in an invisible particle, whose true energy and momentum are not measured in the detector. Nevertheless, a useful educated guess about the invisible momenta can still be obtained by optimizing a suitable invariant mass function. We review and contrast several proposals in the literature for such ansatze: four versions of the M_T2-assisted on-shell reconstruction (MAOS), as well as several variants of the on-shell constrained M_2 variables. We compare the performance of these methods with regards to the mass determination of a…
With the KATRIN experiment, the determination of the absolute neutrino mass scale down to cosmologically favored values has come into reach. We show that this measurement provides the missing link between the Standard Model and the dark sector in scotogenic models, where the suppression of the neutrino masses is economically explained by their only indirect coupling to the Higgs field. We determine the linear relation between the electron neutrino mass and the scalar coupling $λ_5$ associated with the dark neutral scalar mass splitting to be $λ_5=3.1\times10^{-9}\ m_{ν_e}/$eV. This relation th…
