127 research outputs found
Search for single vector-like quark production in hadronic final states at the LHC
No full textIn this paper, we study the discovery potential of a Vector-Like quark (VLB) via the process at the Large Hadron Collider (LHC) with TeV. In the framework of a simplified model, we perform a scan over its parameter space and test its viability following a Monte Carlo analysis developed to include all production and decay dynamics. We use cut-and-count combined with Extreme Gradient Boosting (XGBoost) methods to classify the signal and background events in order to improve the efficiency of signal identification and background rejection. We find that this approach can reduce background events significantly while the signal retention rate is much higher than that of traditional methods, thereby improving the VLB discovery potential. We then calculate the exclusion and discovery capabilities for VLBs and find that the advantages of the cut-and-count plus XGBoost method especially lie in the high-mass region, i.e., m_B > 1500 \text{ GeV}. We finally obtain the following LHC results in terms of the coupling and chiral structure of a singlet heavy VLB interactions: (i) for =0.2 and with 3000 fb, the quark mass can be be excluded (discovered) up to 3000 GeV (2500 GeV); (ii) for =0.2 and with 3000 fb, the exclusion (discovery) region can reach up to 4750 GeV (4250 GeV)
Single production of an exotic vector-like Y quark at future high energy pp colliders
No full textVector-like quarks have been predicted in various new physics scenarios beyond the Standard Model (SM). In a simplified modelling of a (B,Y) doublet including a vector-like quark Y, with charge −43e, there are only two free parameters: the Y coupling κY and mass mY. In the five flavor scheme, we investigate the single production of the Y state decaying into Wb at the Large Hadron Collider (LHC) Run-III and High-Luminosity LHC (HL-LHC) operating at s√ = 14 TeV, the possible High-Energy LHC (HE-LHC) with s√ = 27 TeV as well as the Future Circular Collider in hadron-hadron mode (FCC-hh) with s√ = 100 TeV. Through detailed signal-to-background analyses and detector simulations, we assess the exclusion capabilities of the Y state at the different colliders. We find that this can be improved significantly with increasing collision energy, especially at the HE-LHC and FCC-hh, both demonstrating an obvious advantage with respect to the HL-LHC case in the case of high mY. Assuming a 10% systematic uncertainty on the background event rate, the exclusion capabilities are summarized as follows: (1) the LHC Run-III can exclude the correlated regions of κY∈[0.044,0.5] and mY∈[1000 GeV,3099 GeV] with integrated luminosity L=300 fb−1; (2) the HL-LHC can exclude the correlated regions of κY∈[0.027,0.5] and mY∈[1000 GeV,3653 GeV] with L=3 ab−1; (3) the HE-LHC can exclude the correlated regions of κY∈[0.030,0.5] and mY∈[1000 GeV,4936 GeV] with L=3 ab−1; (4) the FCC-hh can exclude the correlated regions of κY∈[0.051,0.5] and mY∈[1000 GeV,6610 GeV] with L=3 ab−1
Tripletino-like WIMP dark matter in the supersymmetric georgi-Machacek model
No full textThe Supersymmetric Custodial Triplet Model (SCTM), a Supersymmetric generalization of the Georgi-Machacek (GM) model, is constructed by extending the Higgs sector of the Minimal Supersymmetric Standard Model by three triplet chiral Superfields with hypercharge Y=0,\pm 1, in order to maintain the holomorphy of the Superpotential and satisfy the requirements of anomaly cancellation. The global SU(2)_L\otimes SU(2)_R symmetry has to be respected for the Superpotential and soft Supersymmetry breaking sector, where the former will only be broken by the Yukawa couplings and the latter one will be broken spontaneously to the custodial SU(2)_V symmetry after Electro-Weak Symmetry Breaking similar as the GM model. The ensuing complicated spectrum not only gives rich collider phenomenology but also provides more available Weakly Interacting Massive Particle (WIMP) Dark Matter (DM) candidates. In this paper, we explore the viability of WIMP solutions for DM in the SCTM, by considering the increasingly stringent constraints from direct detection DM experiments. Our numerical simulations show that a significant portion of the SCTM parameter space remains viable despite these constraints and will be fully tested in future experiments
Little Higgs dark matter after PandaX-II/LUX-2016 and LHC Run-1
No full textIn the Littlest Higgs model with T-parity (LHT), the T-odd heavy photon (AH) is weakly interacting and can play the role of dark matter. We investigate the lower limit on the mass of AH dark matter under the constraints from Higgs data, EWPOs, Rb, Planck 2015 dark matter relic abundance, PandaX-II/LUX 2016 direct detections and LHC-8 TeV monojet results. We find that (1) Higgs data, EWPOs and Rb can exclude the mass of AH up to 99 GeV. To produce the correct dark matter relic abundance, AH has to co-annihilate with T-odd quarks (qH) or leptons (ℓH); (2) the LUX (PandaX-II) 2016 data can further exclude mAH 540 GeV, for qH-AH co-annihilation; (4) future XENON1T(2017) experiment can fully cover the parameter space of ℓH-AH co-annihilation and will push the lower limit of mAH up to about 640 GeV for qH-AH co-annihilation. © 2016, The Author(s)1111Nsciescopu
Daily Electricity Consumption Forecasting Based on Lazy Learning
No full textDaily electricity consumption is varying randomly. To improve forecasting accuracy, a Lazy Learning (LL) model is proposed. LL aims to build the regression forecasting models upon vectors which are chosen by K-vector nearest neighbors (K-VNN) method. K-VNN can solve overfitting problem and high accuracy can be ensured. Since there are many factors related to electricity consumption, Grey T's correlation degree is used to determine key indexes to further improve the running efficiency of the model. In addition, fuzzy C-means (FCM) clustering is applied to explore the similar scenarios, then the searching scope of LL is reduced. A case studied in one building in Shanghai shows the proposed method can enhance the accuracy and efficiency of electricity consumption forecasting
One-loop effects on top pair production in the littlest Higgs model with T-parity at the LHC
No full textIn this work, we systematically investigate the one-loop corrections to production in the littlest Higgs model with T-parity (LHT) at the LHC for \sqrt{s}=8,14~\mbox{TeV}. We focus on the effects of LHT particles on cross section, polarization asymmetries, spin correlation and charge asymmetry at the LHC. We also study the top quark forward–backward asymmetry at Tevatron and its correlations with the LHC observables. We found that: (1) the contributions of the LHT particles to production can only reach about 1 % at the 14 TeV LHC. Meanwhile, the anomalous top quark forward–backward asymmetry at Tevatron is also hardly to be explained in the LHT model. (2) The parity violating asymmetries in production, such as left–right asymmetry |A
LR| and the polarization |P
t
| can, respectively, reach 1.1 % and 0.5 %, which may have the potential to provide a signal of LHT at the LHC
Daily Electricity Consumption Forecasting Based on Lazy Learning
No full textDaily electricity consumption is varying randomly. To improve forecasting accuracy, a Lazy Learning (LL) model is proposed. LL aims to build the regression forecasting models upon vectors which are chosen by K-vector nearest neighbors (K-VNN) method. K-VNN can solve overfitting problem and high accuracy can be ensured. Since there are many factors related to electricity consumption, Grey T's correlation degree is used to determine key indexes to further improve the running efficiency of the model. In addition, fuzzy C-means (FCM) clustering is applied to explore the similar scenarios, then the searching scope of LL is reduced. A case studied in one building in Shanghai shows the proposed method can enhance the accuracy and efficiency of electricity consumption forecasting
Revisiting <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Z</mml:mi><mml:mi>b</mml:mi><mml:mover accent="true"><mml:mi>b</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:math> couplings in the littlest Higgs model with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>T</mml:mi></mml:math> parity under current experimental constraints
No full textOne-loop QCD correction to top pair production in the littlest Higgs model with T-parity at the LHC
No full textIn this work, we investigate the one-loop QCD correction to top pair production in the littlest Higgs model with T-parity at the LHC. We calculate the relative correction of the top pair production cross-section and top-antitop spin correlation at the LHC for . We find that the relative corrections of top pair production cross-section can reach about , and the top-antitop spin correlation can reach at the 8(14) TeV LHC in the favorable parameter space
Top Partner Production at e+e- Collider in the Littlest Higgs Model with T-Parity
No full textIn the framework of the littlest Higgs Model with T-parity, we discuss the top partner production at future e+e- collider. We calculate the cross sections of the top partner production processes and associated production processes of Higgs and top partner under current constraints. Then, we investigate the observability of the T-odd top partner pair production through the process e+e-→T-T¯-→tt¯AHAH in the tt¯ dilepton channel for two T-odd top partner masses mT-=603 (708) GeV at s=1.5 TeV. We analyze the signal significance depending on the integrated luminosity and find that this signal is promising at the future high energy e+e- collider
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