The mass of the top quark is measured in a data set corresponding to 4.6 fb$^{-1}$ of proton-proton collisions with centre-of-mass energy $\sqrt{s}=7$ TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top-antitop quark pairs with at least six jets in the final state are selected. The substantial background from multijetproduction is modelled with data-driven methods that utilise the number of identified $b$-quark jets and the transverse momentum of the sixth leading jet,which have minimal correlation. The top-quark mass is obtained from template fits to the ratio of three-jet to dijet mass. The three-jet mass is calculated from the three jets produced in a top-quark decay. Using these three jets the dijet mass is obtained from the two jets produced in the $W$ boson decay. The top-quark mass obtained from this fit is thus less sensitive to the uncertainty in the energy measurement of the jets. A binned likelihood fit yields a top-quark mass of $m_{t} = 175.1 \pm 1.4$ (stat) $\pm 1.2$ (syst) GeV.
Recent results from the proton-proton collision data taken by the ATLAS experiment on exotic resonances are presented. A search for $J/ψp$ resonances in $Λ_{b}\rightarrow J/ψp K$ decays with large $p K$ invariant masses is reported. A search for exotic resonances in the four-muon final state is shown.
A measurement of the material in the ATLAS inner detector using secondary hadronic interactions
ATLAS内部探测器用于重建初级碰撞产物强子相互作用的次级顶点，从而探测ATLAS内部区域的物质位置和数量。收集的数据在7 TeV pp碰撞在LHC，与最小的偏置触发，用于与模拟事件的比较。重建的次顶点的空间分辨率范围从~200微米到1毫米。模拟中的整体材料描述被验证在约7%的实验不确定度内。这将导致更好地理解各种物体的重建，如轨道，轻子，喷流和丢失的横向动量。
A search for a new heavy boson $W^{\prime}$ in proton-proton collisions at $\sqrt{s}$ = 13 TeV is presented. The search focuses on the decay of the $W^{\prime}$ to a hadronic top quark and a bottom quark, using the full Run 2 dataset of the ATLAS detector. The hadronic decay of the top quark is identified using DNN-based boosted-object techniques. The dominant background is obtained by a data-driven method with small systematic uncertainties. The results are presented as upper limits on the production cross-section times decay branching ratio for the $W^{\prime}$ boson with right-handed coupli…
Measurement of the top quark pair cross section with ATLAS in pp collisions at sqrt(s) = 7 TeV using final states with an electron or a muon and a hadronically decaying tau lepton
Search for down-type fourth generation quarks with the ATLAS detector in events with one lepton and hadronically decaying W bosons
这封信介绍了在轻子+喷流通道中通过b '->Wt衰变的重下型夸克的成对产生的研究，如b' b '->WtWt->bbWWWW->lvbbqqqqqq。除了需要恰好一个轻子、大的缺失横向动量和至少六个喷注之外，附近喷注对的不变质量被用来识别高横向动量的W玻色子。在ATLAS探测器记录的sqrt（s）= 7 TeV pp碰撞的积分亮度为1.04 fb^-1的数据中，在95%的置信水平下排除了质量小于480 GeV的重降型夸克。
Search for supersymmetry with jets, missing transverse momentum and at least one hadronically decaying tau lepton in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector
Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in pp collisions at sqrt(s)=8 TeV with the ATLAS detector
A search for decays of pair-produced neutral long-lived particles (LLPs) is presented using 139 fb$^{-1}$ of proton-proton collision data collected by the ATLAS detector at the LHC in 2015-2018 at a centre-of-mass energy of 13 TeV. Dedicated techniques were developed for the reconstruction of displaced jets produced by LLPs decaying hadronically in the ATLAS hadronic calorimeter. Two search regions are defined for different LLP kinematic regimes. The observed numbers of events are consistent with the expected background, and limits for several benchmark signals are determined. For a SM Higgs b…
Experimental systematic uncertainties (and object reconstruction) on top physics, their correlations, comparison ATLAS vs CMS (vs Tevatron) and common agreements
Models with extra gauge symmetry were well motivated extensions of the Standard Model. In this paper, we search for an excess of events in search of a heavy neutral gauge boson Z which is fermiophobic. We are looking at llbb final states where the dilepton channel provides the most stringent constraint on the fermiophobic (FB) model. Since Z is fermiophobic, the production of such particles can occur via vector boson fusion, with subsequent decays into WW or Zh. We observe no significant excess of events over the background-only hypothesis and are able to put the constraint on efficiency times…
Measurement of $WW/WZ \to \ell νq q^{\prime}$ production with the hadronically decaying boson reconstructed as one or two jets in $pp$ collisions at $\sqrt{s}=8$ TeV with ATLAS, and constraints on anomalous gauge couplings
Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using 20.3 $fb^{-1}$ of $\sqrt{s}$ = 8 TeV proton-proton collision data
Search for new phenomena with the monojet and missing transverse momentum signature using the ATLAS detector in sqrt(s) = 7 TeV proton-proton collisions
