Examination of the structural and functional versatility of glmS ribozymes by using in vitro selection

Self-cleaving ribozymes associated with the glmS genes of many Gram-positive bacteria are activated by binding to glucosamine-6-phosphate (GlcN6P). Representatives of the glmS ribozyme class function as metabolite-sensing riboswitches whose self-cleavage activities down-regulate the expression of GlmS enzymes that synthesizes GlcN6P. As with other riboswitches, natural glmS ribozyme isolates are highly specific for their target metabolite. Other small molecules closely related to GlcN6P, such as glucose-6-phosphate, cannot activate self-cleavage. We applied in vitro selection methods in an attempt to identify variants of a Bacillus cereus glmS ribozyme that expand the range of compounds that induce self-cleavage. In addition, we sought to increase the number of variant ribozymes of this class to further examine the proposed secondary structure model. Although numerous variant ribozymes were obtained that efficiently self-cleave, none exhibited changes in target specificity. These findings are consistent with the hypothesis that GlcN6P is used by the ribozyme as a coenzyme for RNA cleavage, rather than an allosteric effector

Search for Higgs Boson and Observation of Z Boson through their Decay into a Charm Quark-Antiquark Pair in Boosted Topologies in Proton-Proton Collisions at s\sqrt{s} =13 TeV

A search for the standard model (SM) Higgs boson (H) produced with transverse momentum greater than 450 GeV and decaying to a charm quark-antiquark ($\mathrm{c\bar{c}}$) pair is presented. The search is performed using proton-proton collision data collected at $\sqrt{s}$ = 13 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. Boosted H $\to$$\mathrm{c\bar{c}}$ decay products are reconstructed as a single large-radius jet and identified using a deep neural network charm tagging technique. The method is validated by measuring the Z $\to$$\mathrm{c\bar{c}}$ decay process, which is observed in association with jets at high $p_\mathrm{T}$ for the first time with a signal strength of 1.00 $_{-0.14}^{+0.17}$ (syst) $\pm$ 0.08 (theo) $\pm$ 0.06 (stat), defined as the ratio of the observed process rate to the standard model expectation. The observed (expected) upper limit on $\sigma$(H) $\mathcal{B}$(H $\to$$\mathrm{c\bar{c}}$) is set at 47 (39) times the SM prediction at 95% confidence level

Search for top squarks in the four-body decay mode with single lepton final states in proton-proton collisions at s= \sqrt{s}= 13 TeV

A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark ($\tilde{\mathrm{t}}_{1}$), is presented. The search targets the four-body decay of the $\tilde{\mathrm{t}}_{1}$, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino ($\tilde{\chi}_{1}^{0}$), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between $m(\tilde{\mathrm{t}}_{1})$ and $m(\tilde{\chi}_{1}^{0})$. The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for $m(\tilde{\mathrm{t}}_{1}) - m(\tilde{\chi}_{1}^{0}) =$ 10 and 80 GeV, respectively.A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark (${\overset{\sim }{\textrm{t}}}_1$), is presented. The search targets the four-body decay of the ${\overset{\sim }{\textrm{t}}}_1$, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino (${\overset{\sim }{\chi}}_1^0$), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb$^{−1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between m(${\overset{\sim }{\textrm{t}}}_1$) and m(${\overset{\sim }{\chi}}_1^0$). The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for m(${\overset{\sim }{\textrm{t}}}_1$) − m(${\overset{\sim }{\chi}}_1^0$) = 10 and 80 GeV, respectively.[graphic not available: see fulltext]A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark ($\tilde{\mathrm{t}}_1$), is presented. The search targets the four-body decay of the $\tilde{\mathrm{t}}_1$, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino ($\tilde{\chi}^0_1$), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between $m(\tilde{\mathrm{t}}_1)$ and $m(\tilde{\chi}^0_1)$. The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for $m(\tilde{\mathrm{t}}_1) - m(\tilde{\chi}^0_1$) = 10 and 80 GeV, respectively

Search for top squarks in the four-body decay mode with single lepton final states in proton-proton collisions at s= \sqrt{s}= 13 TeV

Journal of high energy physics 06(6), 060 (2023). doi:10.1007/JHEP06(2023)060 A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark (${\overset{\sim }{\textrm{t}}}_1$), is presented. The search targets the four-body decay of the ${\overset{\sim }{\textrm{t}}}_1$, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino (${\overset{\sim }{\chi}}_1^0$), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb$^{−1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between m(${\overset{\sim }{\textrm{t}}}_1$) and m(${\overset{\sim }{\chi}}_1^0$). The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for m(${\overset{\sim }{\textrm{t}}}_1$) − m(${\overset{\sim }{\chi}}_1^0$) = 10 and 80 GeV, respectively.[graphic not available: see fulltext] Published by SISSA, [Trieste