Actual problem in breeding onion (Allium cepa. L) is the identification of cytoplasm type in varieties and F1 hybrids. To create a parent sterile fixing line, is required a cytoplasm of type N. ...However, heterozygous F1 hybrids and new onion varieties obtained from subsequent generations from F1 fertility hybrids that possess economically valuable traits and meet market requirements are not suitable for creating a sterile fixing line from them, because all hybrid plants has 100% S-cytoplasm or T-cytoplasm type. In order to determine the most desirable parent component with subsequent use in the selection process, the Laboratory of Selection and Seed Production of Onion Cultures of the Gavrish company conducted a phenotypic and molecular analysis of collection samples of onions for the feature of male sterility. The material for research was grown according to the generally accepted technologies for the zone in the city of Krymsk, Krasnodar Territory. Phenotypic analysis of the manifestation of the "male sterility" feature was carried out with the help of visual analysis. As a result of the work, were identified varieties and F1 hybrids that can be used as genetic sources for the creation of new sterile lines and lines of sterility fixers, as well as samples to be used as pollinators. In the future, these lines will be used to create heterotic F1 hybrids with high indicators of economic characteristics with given properties.
Abstract Results of the Model Unspecific Search in CMS (MUSiC), using proton–proton collision data recorded at the LHC at a centre-of-mass energy of 13 $$\,\text {TeV}$$ TeV , corresponding to an ...integrated luminosity of 35.9 $$\,\text {fb}^{-1}$$ fb - 1 , are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.
Abstract The production of Z boson pairs in proton–proton ( $${\mathrm{p}} {\mathrm{p}} $$ p p ) collisions, $${{\mathrm{p}} {\mathrm{p}} \rightarrow ({\mathrm{Z}}/\gamma ^*)({\mathrm{Z}}/\gamma ^*) ...\rightarrow 2\ell 2\ell '}$$ p p → ( Z / γ ∗ ) ( Z / γ ∗ ) → 2 ℓ 2 ℓ ′ , where $${\ell ,\ell ' = {\mathrm{e}}}$$ ℓ , ℓ ′ = e or $${{\upmu }}$$ μ , is studied at a center-of-mass energy of 13 $$\,\text {TeV}$$ TeV with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137 $$\,\text {fb}^{-1}$$ fb - 1 , collected during 2016–2018. The $${\mathrm{Z}} {\mathrm{Z}} $$ Z Z production cross section, $$\sigma _{\text {tot}} ({\mathrm{p}} {\mathrm{p}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} ) = 17.4 \pm 0.3 \,\text {(stat)} \pm 0.5 \,\text {(syst)} \pm 0.4 \,\text {(theo)} \pm 0.3 \,\text {(lumi)} \text { pb} $$ σ tot ( p p → Z Z ) = 17.4 ± 0.3 (stat) ± 0.5 (syst) ± 0.4 (theo) ± 0.3 (lumi) pb , measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region $${60< m_{\ell ^+\ell ^-} < 120\,\text {GeV}}$$ 60 < m ℓ + ℓ - < 120 GeV is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous $${\mathrm{Z}} {\mathrm{Z}} {\mathrm{Z}} $$ Z Z Z and $${{\mathrm{Z}} {\mathrm{Z}} \gamma }$$ Z Z γ couplings.
Abstract A search is presented for supersymmetric partners of the top quark (top squarks) in final states with two oppositely charged leptons (electrons or muons), jets identified as originating from ...$${\text {b}}$$ b quarks, and missing transverse momentum. The search uses data from proton-proton collisions at $$\sqrt{s}=13\,\text {TeV} $$ s = 13 TeV collected with the CMS detector, corresponding to an integrated luminosity of 137 $$\,{\text {fb}}^{-1}$$ fb - 1 . Hypothetical signal events are efficiently separated from the dominant top quark pair production background with requirements on the significance of the missing transverse momentum and on transverse mass variables. No significant deviation is observed from the expected background. Exclusion limits are set in the context of simplified supersymmetric models with pair-produced lightest top squarks. For top squarks decaying exclusively to a top quark and a lightest neutralino, lower limits are placed at $$95\%$$ 95 % confidence level on the masses of the top squark and the neutralino up to 925 and 450 $$\,\text {GeV}$$ GeV , respectively. If the decay proceeds via an intermediate chargino, the corresponding lower limits on the mass of the lightest top squark are set up to 850 $$\,\text {GeV}$$ GeV for neutralino masses below 420 $$\,\text {GeV}$$ GeV . For top squarks undergoing a cascade decay through charginos and sleptons, the mass limits reach up to 1.4 $$\,\text {TeV}$$ TeV and 900 $$\,\text {GeV}$$ GeV respectively for the top squark and the lightest neutralino.
Abstract Normalised multi-differential cross sections for top quark pair ($$\hbox {t}{\bar{\hbox {t}}}$$ tt¯ ) production are measured in proton-proton collisions at a centre-of-mass energy of ...13$$\,{\text {TeV}}$$ TeV using events containing two oppositely charged leptons. The analysed data were recorded with the CMS detector in 2016 and correspond to an integrated luminosity of $$35.9{\,{\text {fb}}^{-1}} $$ 35.9fb-1 . The double-differential $$\hbox {t}{\bar{\hbox {t}}}$$ tt¯ cross section is measured as a function of the kinematic properties of the top quark and of the $$\hbox {t}{\bar{\hbox {t}}}$$ tt¯ system at parton level in the full phase space. A triple-differential measurement is performed as a function of the invariant mass and rapidity of the $$\hbox {t}{\bar{\hbox {t}}}$$ tt¯ system and the multiplicity of additional jets at particle level. The data are compared to predictions of Monte Carlo event generators that complement next-to-leading-order (NLO) quantum chromodynamics (QCD) calculations with parton showers. Together with a fixed-order NLO QCD calculation, the triple-differential measurement is used to extract values of the strong coupling strength $$\alpha _{S}$$ αS and the top quark pole mass ($$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole ) using several sets of parton distribution functions (PDFs). The measurement of $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole exploits the sensitivity of the $$\hbox {t}{\bar{\hbox {t}}}$$ tt¯ invariant mass distribution to $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole near the production threshold. Furthermore, a simultaneous fit of the PDFs, $$\alpha _{S}$$ αS , and $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole is performed at NLO, demonstrating that the new data have significant impact on the gluon PDF, and at the same time allow an accurate determination of $$\alpha _{S}$$ αS and $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole . The values $$\alpha _{S}(m_{{\text {Z}}}) = 0.1135{}^{+0.0021}_{-0.0017}$$ αS(mZ)=0.1135-0.0017+0.0021 and $$m_{{\text {t}}}^{{\text {pole}}} = 170.5 \pm 0.8 \,{\text {GeV}} $$ mtpole=170.5±0.8GeV are extracted, which account for experimental and theoretical uncertainties, the latter being estimated from NLO scale variations. Possible effects from Coulomb and soft-gluon resummation near the $$\hbox {t}{\bar{\hbox {t}}}$$ tt¯ production threshold are neglected in these parameter extractions. A rough estimate of these effects indicates an expected correction of $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole of the order of $$+1 \,{\text {GeV}} $$ +1GeV , which can be regarded as additional theoretical uncertainty in the current $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole extraction.
Abstract A measurement is presented of differential cross sections for t-channel single top quark and antiquark production in proton–proton collisions at a centre-of-mass energy of 13$$\,\text ...{Te}\text {V}$$ Te by the CMS experiment at the LHC. From a data set corresponding to an integrated luminosity of 35.9$$\,\text {fb}^{-1}$$ fb-1 , events containing one muon or electron and two or three jets are analysed. The cross section is measured as a function of the top quark transverse momentum ($$p_{\mathrm{T}} $$ pT ), rapidity, and polarisation angle, the charged lepton $$p_{\mathrm{T}} $$ pT and rapidity, and the $$p_{\mathrm{T}} $$ pT of the $$\text {W}{}{}$$ W boson from the top quark decay. In addition, the charge ratio is measured differentially as a function of the top quark, charged lepton, and $$\text {W}{}{}$$ W boson kinematic observables. The results are found to be in agreement with standard model predictions using various next-to-leading-order event generators and sets of parton distribution functions. Additionally, the spin asymmetry, sensitive to the top quark polarisation, is determined from the differential distribution of the polarisation angle at parton level to be $$0.440 \pm 0.070$$ 0.440±0.070 , in agreement with the standard model prediction.
Abstract A search for $$\text {W}\text {W}$$ WW production from double-parton scattering processes using same-charge electron-muon and dimuon events is reported, based on proton-proton collision data ...collected at a center-of-mass energy of $$13\,\text {TeV} $$ 13TeV . The analyzed data set corresponds to an integrated luminosity of $$77.4{\,\text {fb}^{-1}} $$ 77.4fb-1 , collected using the CMS detector at the LHC in 2016 and 2017. Multivariate classifiers are used to discriminate between the signal and the dominant background processes. A maximum likelihood fit is performed to extract the signal cross section. This leads to the first evidence for $$\text {W}\text {W}$$ WW production via double-parton scattering, with a significance of 3.9 standard deviations. The measured inclusive cross section is $$1.41\pm 0.28\,\text {(stat)} \pm 0.28\,\text {(syst)} \,\text {pb} $$ 1.41±0.28(stat)±0.28(syst)pb .
Abstract Two related searches for phenomena beyond the standard model (BSM) are performed using events with hadronic jets and significant transverse momentum imbalance. The results are based on a ...sample of proton–proton collisions at a center-of-mass energy of $$13\,\text {Te}\text {V} $$ 13Te , collected by the CMS experiment at the LHC in 2016–2018 and corresponding to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb-1 . The first search is inclusive, based on signal regions defined by the hadronic energy in the event, the jet multiplicity, the number of jets identified as originating from bottom quarks, and the value of the kinematic variable $$M_{\mathrm {T2}}$$ MT2 for events with at least two jets. For events with exactly one jet, the transverse momentum of the jet is used instead. The second search looks in addition for disappearing tracks produced by BSM long-lived charged particles that decay within the volume of the tracking detector. No excess event yield is observed above the predicted standard model background. This is used to constrain a range of BSM models that predict the following: the pair production of gluinos and squarks in the context of supersymmetry models conserving R-parity, with or without intermediate long-lived charginos produced in the decay chain; the resonant production of a colored scalar state decaying to a massive Dirac fermion and a quark; or the pair production of scalar and vector leptoquarks each decaying to a neutrino and a top, bottom, or light-flavor quark. In most of the cases, the results obtained are the most stringent constraints to date.
Abstract The standard model (SM) production of four top quarks ($$\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $$ tt¯tt¯ ) in proton–proton collisions is studied by the CMS ...Collaboration. The data sample, collected during the 2016–2018 data taking of the LHC, corresponds to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb-1 at a center-of-mass energy of 13$$\,\text {TeV}$$ TeV . The events are required to contain two same-sign charged leptons (electrons or muons) or at least three leptons, and jets. The observed and expected significances for the $$\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $$ tt¯tt¯ signal are respectively 2.6 and 2.7 standard deviations, and the $$\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $$ tt¯tt¯ cross section is measured to be $$12.6^{+5.8}_{-5.2}\,\text {fb} $$ 12.6-5.2+5.8fb . The results are used to constrain the Yukawa coupling of the top quark to the Higgs boson, $$y_{\text {t}}$$ yt , yielding a limit of $$|y_{\text {t}}/y_{\text {t}}^{\mathrm {SM}} | < 1.7$$ |yt/ytSM|<1.7 at $$95\%$$ 95% confidence level, where $$y_{\text {t}}^{\mathrm {SM}}$$ ytSM is the SM value of $$y_{\text {t}}$$ yt . They are also used to constrain the oblique parameter of the Higgs boson in an effective field theory framework, $$\hat{H}<0.12$$ H^<0.12 . Limits are set on the production of a heavy scalar or pseudoscalar boson in Type-II two-Higgs-doublet and simplified dark matter models, with exclusion limits reaching 350–470$$\,\text {GeV}$$ GeV and 350–550$$\,\text {GeV}$$ GeV for scalar and pseudoscalar bosons, respectively. Upper bounds are also set on couplings of the top quark to new light particles.
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