Polarization effects in early SUSY searches at the CERN LHC

Abstract

An on-shell effective theory (OSET) approach has been widely used in searches of various supersymmetric signals, in particular, gluino/squark pairs with long cascade decay chains in which complete matrix element calculations may encounter high dimensional integrations. On the other hand, leptons from polarized chargino decays may show a significant boost effect in some scenarios and simulation without polarization information may underestimate or overestimate the lepton p T cut efficiencies in the first place. We study the polarization effects in leptonic decaying charginos from squarks or gluinos. Taking the polarization effects into account, we find it still justifiable to take only the OSET approach for a large parameter region, for instance, the first two generation squarks due to indistinguishable final states as well as a flat angular distribution in the motion of the lepton. On the other hand, we use the leptonic stop to illustrate the feature and find that the lepton p T cut efficiencies in cross section measurements can have maximally 25 % reduction or maximally 17 % enhancement in comparison with the kinematics-only approach. The signal rates after the cuts simulated by OSET are then underestimated/overestimated and the real bound on the squark/gluino should be more stringent or loose for a specific choice of the chargino and one can take the simulated efficiencies as a fast-simulation factor to multiply to the OSET simulated results.

Effect of Thermoplastic Starch and Photocrosslinking on the Properties and Morphology of Electrospun Poly(ethylene‐co‐vinyl alcohol) Mats

“…Their barrier properties largely depend on ethylene content, crystallinity, temperature, and humidity, and are attributed to the high cohesive energy density of the resin . Recently, a completely different application was found for these materials: electrospun EVOH fiber mats have been prepared and studied for potential use as dressing materials for the treatment of skin wounds, partly due to their good fluid uptake ability (FUA) .…”

“…Although, extruded starch–EVOH blends have generated significant commercial interest owing to their pliability, toughness, and ability to be processed at temperatures similar to polyethylene or polypropylene, EVOH/TPS blends have not been electrospun to date . Furthermore, apart from their good hydrocarbon barrier properties, these fibrous materials will exhibit high porosity, biodegradability, and biocompatibility, important factors for potential candidates in skin wound treatment .…”

Polarization of top and chargino from stop decay in natural SUSY

“…It should be noted that the top quark produced from stop decay is polarized due to the parity-violating interactions of stop. The polarization effects can be measured from the kinematics of the decay products [20][21][22][23][24][25][26][27][28], which can be utilized to reveal the features of stop and other non-SM couplings of the third generation quarks [29][30][31][32][33][34][35]. For example, the top polarization was used to probe the mixing in the stop sector at future lepton colliders [36].…”

Virtual contributions from $D^{\ast}(2007)^0$ and $D^{\ast}(2010)^{\pm}$ in the $B\to Dπh$ decays

“…In order to extract the most information on the involved strong and weak dynamics from the experimental data of the three-body B decays, different methods have been adopted, such as the isospin, U-spin and/or flavor SU (3) symmetries [46][47][48][49][50][51][52][53][54][55], the QCD factorization [56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71] and the PQCD approach [72][73][74][75][76][77][78] in abundant works. While threebody hadronic B decays are known experimentally, in most cases, to be dominated by the low energy scalar, vector and tensor resonances, which could be analysed in the quasi-two-body framework by neglecting the three-body effects and the rescattering effects [79,80].…”

“…B0 → D * + K − → D 0 π + K − 0.72 +0.36 −0.24 × 10 −5 (0.81 ± 0.15 ± 0.20 ± 0.27 ± 0.09) × 10 −5 [18] B − → D * 0 π − → D + π − π − 1.91 +0.89 −0.63 × 10 −4 (2.23 ± 0.32) × 10 −4 [14] ∼ 1.09 × 10 −4 [16] (1.09 ± 0.07 ± 0.07 ± 0.24 ± 0.07) × 10 −4 [21] B − → D * 0 K − → D + π − K − 1.48 +0 67. −0.49 × 10 −5 (5.6 ± 1.7 ± 1.0 ± 1.1 ± 0.4) × 10 −6[17] …”