522 research outputs found

    Long-distance optical-conveyor-belt transport of ultracold 133 Cs and 87 Rb atoms

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    We report on the transport of a thermal cloud of ultracold cesium and rubidium atoms over about 37 cm in under 25 ms using an optical conveyor belt formed by two counterpropagating beams with a controllable frequency difference that generate a movable optical lattice. By carefully selecting the waists and focus positions, we are able to use two static Gaussian beams for the transport, avoiding the need for a Bessel beam or variable-focus lenses. We characterize the transport efficiency for both species, including a comparison of different transport trajectories, gaining insight into the loss mechanisms and finding the minimum jerk trajectory to be optimum. Using the optimized parameters, we are able to transport up to 7×106 cesium or rubidium atoms with an efficiency up to 75%. To demonstrate the viability of our transport scheme for experiments employing quantum gas microscopy, we produce Bose-Einstein condensates of either species after transport and present measurements of the simultaneous transport of both species

    London Trauma Conference 2015

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    Phospholipase D: Enzymology, Functionality, and Chemical Modulation

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    Extracting the speed of sound in the strongly interacting matter created in ultrarelativistic lead-lead collisions at the LHC

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    International audienceUltrarelativistic nuclear collisions create a strongly interacting state of hot and dense quark-gluon matter that exhibits a remarkable collective flow behavior with minimal viscous dissipation. To gain deeper insights into its intrinsic nature and fundamental degrees of freedom, we extracted the speed of sound in this medium created using lead-lead (PbPb) collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 0.607 nb1^{-1}. The measurement is performed by studying the multiplicity dependence of the average transverse momentum of charged particles emitted in head-on PbPb collisions. Our findings reveal that the speed of sound in this matter is nearly half the speed of light, with a squared value of 0.241 ±\pm 0.002 (stat) ±\pm 0.016 (syst) in natural units. The effective medium temperature, estimated using the mean transverse momentum, is 219 ±\pm 8 (syst) MeV. The measured squared speed of sound at this temperature aligns precisely with predictions from lattice quantum chromodynamic (QCD) calculations. This result provides a stringent constraint on the equation of state of the created medium and direct evidence for a deconfined QCD phase being attained in relativistic nuclear collisions

    Search for CPCP violation in ttH and tH production in multilepton channels in proton-proton collisions at s\sqrt{s} = 13 TeV

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    International audienceThe charge-parity (CP) structure of the Yukawa interaction between the Higgs (H) boson and the top quark is measured in a data sample enriched in the tt \overline{\textrm{t}} H and tH associated production, using 138 fb1^{−1} of data collected in proton-proton collisions at s \sqrt{s} = 13 TeV by the CMS experiment at the CERN LHC. The study targets events where the H boson decays via H → WW or H → ττ and the top quarks decay via t → Wb: the W bosons decay either leptonically or hadronically, and final states characterized by the presence of at least two leptons are studied. Machine learning techniques are applied to these final states to enhance the separation of CP -even from CP -odd scenarios. Two-dimensional confidence regions are set on κt_{t} and κt \overset{\sim }{\kappa } _{t}, which are respectively defined as the CP -even and CP -odd top-Higgs Yukawa coupling modifiers. No significant fractional CP -odd contributions, parameterized by the quantity |fCPHtt {f}_{CP}^{\textrm{Htt}} | are observed; the parameter is determined to be |fCPHtt {f}_{CP}^{\textrm{Htt}} | = 0.59 with an interval of (0.24, 0.81) at 68% confidence level. The results are combined with previous results covering the H → ZZ and H → γγ decay modes, yielding two- and one-dimensional confidence regions on κt_{t} and κt \overset{\sim }{\kappa } _{t}, while |fCPHtt {f}_{CP}^{\textrm{Htt}} | is determined to be |fCPHtt {f}_{CP}^{\textrm{Htt}} | = 0.28 with an interval of |fCPHtt {f}_{CP}^{\textrm{Htt}} | < 0.55 at 68% confidence level, in agreement with the standard model CP -even prediction of |fCPHtt {f}_{CP}^{\textrm{Htt}} | = 0.[graphic not available: see fulltext

    Search for a charged Higgs boson decaying into a heavy neutral Higgs boson and a W boson in proton-proton collisions at s=\sqrt{s} = 13 TeV

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    A search for a charged Higgs boson H~±{\mathrm{\tilde{H}^{\pm}}} decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016-2018 at s=\sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{-1}. The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H~±{\mathrm{\tilde{H}^{\pm}}} in the mass range of 300-700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H~±{\mathrm{\tilde{H}^{\pm}}} mass of 300 GeV to 0.019 pb for a mass of 700 GeV. These are the first limits on H~±{\mathrm{\tilde{H}^{\pm}}} production in the H~±HW±{\mathrm{\tilde{H}^{\pm}}} \to \mathrm{H} \mathrm{W^{\pm}} decay channel at the LHC.A search for a charged Higgs boson H±^{±} decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016–2018 at s \sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{−1}. The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H±^{±} in the mass range of 300–700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H±^{±} mass of 300 Ge V to 0.019 pb for a mass of 700 GeV. These are the first limits on H±^{±} production in the H±^{±}→ HW±^{±} decay channel at the LHC.[graphic not available: see fulltext]A search for a charged Higgs boson H±^\pm decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016-2018 at s\sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{-1}. The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H±^\pm in the mass range of 300-700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H±^\pm mass of 300 GeV to 0.019 pb for a mass of 700 GeV. These are the first limits on H±^\pm production in the H±^\pm \to HW±^\pm decay channel at the LHC

    Measurement of the Higgs boson inclusive and differential fiducial production cross sections in the diphoton decay channel with pp collisions at s \sqrt{s} = 13 TeV

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    The measurements of the inclusive and differential fiducial cross sections of the Higgs boson decaying to a pair of photons are presented. The analysis is performed using proton-proton collisions data recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 137 fb1^{−1}. The inclusive fiducial cross section is measured to be σfid=73.45.3+5.4(stat)2.2+2.4(syst) {\sigma}_{\textrm{fid}}={73.4}_{-5.3}^{+5.4}{\left(\textrm{stat}\right)}_{-2.2}^{+2.4}\left(\textrm{syst}\right) fb, in agreement with the standard model expectation of 75.4 ± 4.1 fb. The measurements are also performed in fiducial regions targeting different production modes and as function of several observables describing the diphoton system, the number of additional jets present in the event, and other kinematic observables. Two double differential measurements are performed. No significant deviations from the standard model expectations are observed.[graphic not available: see fulltext

    Search for resonant and nonresonant production of pairs of dijet resonances in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A search for pairs of dijet resonances with the same mass is conducted in final states with at least four jets. Results are presented separately for the case where the four jet production proceeds via an intermediate resonant state and for nonresonant production. The search uses a data sample corresponding to an integrated luminosity of 138 fb1^{−1} collected by the CMS detector in proton-proton collisions at s \sqrt{s} = 13 TeV. Model-independent limits, at 95% confidence level, are reported on the production cross section of four-jet and dijet resonances. These first LHC limits on resonant pair production of dijet resonances via high mass intermediate states are applied to a signal model of diquarks that decay into pairs of vector-like quarks, excluding diquark masses below 7.6 TeV for a particular model scenario. There are two events in the tails of the distributions, each with a four-jet mass of 8 TeV and an average dijet mass of 2 TeV, resulting in local and global significances of 3.9 and 1.6 standard deviations, respectively, if interpreted as a signal. The nonresonant search excludes pair production of top squarks with masses between 0.50 TeV to 0.77 TeV, with the exception of a small interval between 0.52 and 0.58 TeV, for supersymmetric R-parity-violating decays to quark pairs, significantly extending previous limits. Here, the most significant excess above the predicted background occurs at an average dijet mass of 0.95 TeV, for which the local and global significances are 3.6 and 2.5 standard deviations, respectively.[graphic not available: see fulltext

    Search for nonresonant pair production of highly energetic Higgs bosons decaying to bottom quarks

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    A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb1^{-1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ2V{\kappa_{2\mathrm{V}}} , excluding κ2V={\kappa_{2\mathrm{V}}} = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (HH) pair production via gluon and vector boson (VV) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb1^{−1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted HH pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the HH self-coupling and the quartic VVHH couplings, κ2Vκ_{2V}, excluding κ2V=0κ_{2V} = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb-1 collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ2V, excluding κ2V=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (HH) pair production via gluon and vector boson (VV) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb1^{−1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted HH pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the HH self-coupling and the quartic VVHH couplings, κ2Vκ_{2V}, excluding κ2V=0κ_{2V} = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb-1 collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ2V, excluding κ2V=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (HH) pair production via gluon and vector boson (VV) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb1^{−1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted HH pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the HH self-coupling and the quartic VVHH couplings, κ2Vκ_{2V}, excluding κ2V=0κ_{2V} = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb-1 collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ2V, excluding κ2V=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (HH) pair production via gluon and vector boson (VV) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb1^{−1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted HH pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the HH self-coupling and the quartic VVHH couplings, κ2Vκ_{2V}, excluding κ2V=0κ_{2V} = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb-1 collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ2V, excluding κ2V=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (HH) pair production via gluon and vector boson (VV) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb1^{−1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted HH pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the HH self-coupling and the quartic VVHH couplings, κ2Vκ_{2V}, excluding κ2V=0κ_{2V} = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb-1 collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ2V, excluding κ2V=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb1^{-1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ2V\kappa_{2V}, excluding κ2V\kappa_{2V} = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values
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