We present a detailed study of the collider observable m T 2 applied for pair-produced superparticles decaying to visible particles and a pair of invisible lightest supersymmetric particles (LSPs). Analytic expressions of the maximum of m T 2 over all events (m max T 2 ) are derived. It is noticed that if the decay product of each superparticle involves more than one visible particle, m max T 2 being a function of the trial LSP mass m χ has a kink structure at m χ = true LSP mass, which can be used to determine the mother superparticle mass and the LSP mass simultaneously. To see how well m max T 2 can be constructed from collider data, a Monte-Carlo analysis of the gluino m T 2 is performed for some superparticle spectra. * After [6], the kink structure of the endpoint values of transverse mass observable has been discussed also in [7,8]. For other approaches to measure superparticle masses at hadron collider, see [4,9,10,11].

We introduce a new observable, "gluino m_{T2}," which is an application of the Cambridge m_{T2} variable to the process where gluinos are pair produced in a proton-proton collision and each gluino subsequently decays into two quarks and one lightest supersymmetric particle, i.e., g[over ]g[over ]-->qqchi[over ]_{1};{0}qqchi[over ]_{1};{0}. We show that the gluino m_{T2} can be utilized to measure the gluino mass and the lightest neutralino mass separately and also the 1st and 2nd generation squark masses if squarks are lighter than the gluino, thereby providing a good first look at the pattern of sparticle masses experimentally.

We propose a scheme to assign a 4-momentum to each WIMP in new physics event producing a pair of mother particles each of which decays to an invisible weakly interacting massive particle (WIMP) plus some visible particle(s). The transverse components are given by the value that determines the event variable M T 2 , while the longitudinal component is determined by the on-shell condition on the mother particle. Although it does not give the true WIMP momentum in general, this M T 2 -assisted on-shell reconstruction of missing momenta provides kinematic variables well correlated to the true WIMP momentum, and thus can be useful for an experimental determination of new particle properties. We apply this scheme to some processes to measure the mother particle spin, and find that spin determination is possible even without a good knowledge of the new particle masses. PACS numbers:1 The Large Hadron Collider (LHC) at CERN will explore soon the TeV energy scale where new physics beyond the Standard Model (SM) is likely to reveal itself. There are two major motivations for new physics at the TeV scale, one is the hierarchy problem and the other

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We revisit the flavor-changing processes involving an axion-like particle (ALP) in the context of generic ALP effective lagrangian with a discussion of possible UV completions providing the origin of the relevant bare ALP couplings. We focus on the minimal scenario that ALP has flavor-conserving couplings at tree level, and the leading flavor-changing couplings arise from the loops involving the Yukawa couplings of the Standard Model fermions. We note that such radiatively generated flavor-changing ALP couplings can be easily suppressed in field theoretic ALP models with sensible UV completion. We discuss also the implication of our result for string theoretic ALP originating from higher-dimensional p-form gauge fields, for instance for ALP in large volume string compactification scenario. *