Date

Evidence for a Resonant Structure of the Hadron Production from e+ e- Annihilations in the 1700-MeV-1950-MeV Center-Of-Mass Energy Region

Ambrosio, M. ; Barbarino, G. ; Barbiellini, G. ; et al.
Phys.Lett.B 68 (1977) 397-401, 1977.
Inspire Record 119882 DOI 10.17182/hepdata.27553

We present experimental evidence for a resonant behaviour of the hadron production from e + e − annihilations at the e + e − storage ring ADONE. A Breit-Wigner fit to the enhancement present between 1800 and 1850 MeV gives the following parameters M = 1812 −13 +7 MeV, Γ = 34 −15 +21 MeV.

1 data table

MULTIHADRON EVENTS (AT LEAST THREE CHARGED TRACKS) PER UNIT LUMINOSITY.


Evidence for a Resonant Behavior in e+ e- Annihilation Into Hadrons, Around 1820-MeV, at ADONE

Bacci, C. ; Baldini-Celio, R. ; Capon, G. ; et al.
Phys.Lett.B 68 (1977) 393-396, 1977.
Inspire Record 119881 DOI 10.17182/hepdata.27562

Multihadron production has been measured at the Adone e + e − storage ring in the c.m. energy region 1600 ÷ 1900 MeV. A resonant behaviour is observed, centered at 1819 ± 5 (±2) MeV, with a width of 24 ± 5 (±4) MeV. This effect is observed only in the events with 3 or 4 charged particles together with photons, but not in those without photons.

1 data table

MULTIHADRON EVENTS (3 OR 4 CHARGED PARTICLES PLUS ONE OR MORE PHOTONS DETECTED) PER UNIT LUMINOSITY. RESONANCE NOT SEEN IN EVENTS WITH NO PHOTONS.


Evidence for the Existence of a New Vector Meson of Mass 1.82-GeV Observed in e+ e- Annihilations at ADONE

Bernabei, R. ; d'Angelo, S. ; Esposito, B. ; et al.
Phys.Lett.B 68 (1977) 389-392, 1977.
Inspire Record 119878 DOI 10.17182/hepdata.27563

Evidence is presented for the occurrence in e + e − annihilation of a new vector meson of mass 1821 ± 16 MeV and Γ = 31 ± 15 MeV.

1 data table

MULTIHADRON EVENTS (AT LEAST THREE CHARGED TRACKS WITH ZERO OR MORE PHOTONS) PER UNIT LUMINOSITY.


The Real Part of the Forward Proton Proton Scattering Amplitude Measured at the CERN Intersecting Storage Rings

Amaldi, U. ; Cocconi, G. ; Diddens, A.N. ; et al.
Phys.Lett.B 66 (1977) 390-394, 1977.
Inspire Record 110800 DOI 10.17182/hepdata.27584

The real part of the proton proton elastic scattering amplitude has been determined from its interference with the Coulomb amplitude at total centre-of-mass energies up to 62 GeV. The observed steady increase of ϱ with energy indicates that the total proton proton cross section continues to increase well beyond this energy.

2 data tables

No description provided.

USING SIG AND SLOPE OBTAINED FROM INTERPOLATIONS OF PREVIOUS MEASUREMENTS.


A Measurement of the Cross-Section of the Reaction p p --> n Delta++ (1232) at ISR Energies

Kwak, N. ; Nagy, E. ; Regler, M. ; et al.
Phys.Lett.B 62 (1976) 359-362, 1976.
Inspire Record 108757 DOI 10.17182/hepdata.27678

A measurement of the cross section of the charge-exchange reaction pp→ Δ ++ (1232)n at √ s = 23, 31 and 45 GeV at the CERN-ISR is reported. The energy dependence continues to follow a power law p lab − n with n = 1.94 ± 0.03 indicating dominance of one-pion exchange at the lowest ISR energy; there is some evidence for deviation from this at the higher ISR energies.

3 data tables

No description provided.

No description provided.

No description provided.


Search for excited tau leptons in the $\tau\tau\gamma$ final state in pp collisions at $\sqrt{s}=13\,\mathrm{TeV}$

The CMS collaboration
CMS-PAS-EXO-22-007, 2024.
Inspire Record 2799063 DOI 10.17182/hepdata.151282

We report the results of a test of the compositeness of the heaviest charged lepton, $\tau$, using data collected in proton-proton collisions at a center of mass energy of 13 TeV at the Large Hadron Collider at CERN in 2016-2018, corresponding to an integrated luminosity of $138\,\mathrm{fb}^{-1}$. We seek tau lepton pair production in which one tau lepton is produced in an excited state and decays to a ground state tau lepton and photon. The analysis selects events with two isolated tau lepton decay candidates plus a high energy photon. The mass of the excited tau lepton is reconstructed using the missing transverse momentum in the event, assuming the momentum of the neutrinos from each tau lepton decay lie along the visible tau lepton decay product direction. We observe no excess of events above the standard model background prediction and use this null result to set lower bounds on the excited tau lepton mass. For a compositeness scale $\Lambda$ equal to the excited tau lepton mass (10 TeV), we exclude excited tau leptons with masses below 4700 GeV (2800 GeV).

14 data tables

Signal process cutflow for all taustar hypothesis masses, channels, and years. Cut descriptions: - numLeps : 1e0mu for ETau, 0e1mu For muTau, 0e0mu for TauTau - havePair : 1e + 1tauh for ETau, 1mu + 1tauh for MuTau, 2tauh for TauTau - trigger : passed appropriate high level trigger (HLT) for channel and year - m_vis : Visible mass of pair is >= 100 GeV - Zveto : No Z->ee or Z->mumu pairs - bveto : No btagged jets in event (only for ETau and MuTau) - gamma20GeV : have a photon with pt>20GeV - gamma100GeV : have a photon with pt>100GeV

Background-only-fit total covariance matrix for all channels and regions. Values are extracted from the Higgs Combine tool's fitDiagnostics option. Please see associated image ("fitRegions.pdf") for guide on region and channel setup.

Background-only-fit total covariance matrix for all channels and regions. Values are extracted from the Higgs Combine tool's fitDiagnostics option. Please see associated image ("fitRegions.pdf") for guide on region and channel setup.

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Version 2
Search for pair production of heavy particles decaying to a top quark and a gluon in the lepton+jets final state at sqrt(s) = 13 TeV

The CMS collaboration
CMS-PAS-B2G-22-005, 2024.
Inspire Record 2814778 DOI 10.17182/hepdata.153717

A search is presented for the pair production of new heavy resonances, each decaying into a top quark or antiquark and a gluon. The analysis uses data recorded with the CMS detector from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 $\text{fb}^{-1}$. Events with one muon or electron, multiple jets, and missing transverse momentum are selected. After using a deep neural network to enrich the data sample with signal-like events, distributions in the scalar sum of the transverse momenta of all reconstructed objects are analyzed in search for a signal. No significant deviations from the standard model predictions are found. Upper limits at $95\%$ confidence level are set on the product of cross section times branching fraction squared for the pair production of two excited top quarks in the $\mathrm{t}^{*} \to \mathrm{t}\mathrm{g}$ decay channel. The upper limits range from 0.12 pb to 0.8 fb for a $\text{t}^{*}$ with spin-1/2 and from 0.015 pb to 1.0 fb for a $\text{t}^{*}$ with spin-3/2. This corresponds to mass exclusion limits up to 1050 and 1700 GeV for spin-1/2 and spin-3/2 $\mathrm{t}^{*}$ particles, respectively.

4 data tables

Expected and observed 95% CL upper limits on the product of the $t^{*} \overline{t}^{*}$ production cross section and the branching fraction squared $BR^2(t^{*} \rightarrow tg)$ for a spin-1/2 $t^{*}$ as a function of $m_{t^{*}}$. The inner (green) and outer (yellow) bands give the central probability intervals containing 68 and 95% of the expected upper limits under the background-only hypothesis. The cross section predicted by theory, following an EFT approach, is shown in blue, assuming $BR(t^{*} \rightarrow tg)=1$.

Expected and observed 95% CL upper limits on the product of the $t^{*} \overline{t}^{*}$ production cross section and the branching fraction squared $BR^2(t^{*} \rightarrow tg)$ for a spin-3/2 $t^{*}$ as a function of $m_{t^{*}}$. The inner (green) and outer (yellow) bands give the central probability intervals containing 68 and 95% of the expected upper limits under the background-only hypothesis. The cross section predicted by theory, following an EFT approach, is shown in blue, assuming $BR(t^{*} \rightarrow tg)=1$. The results of the previous CMS analysis, using data corresponding to an integrated luminosity of 35.9 $fb^{-1}$, are shown in red.

Distributions in $S_T$ in the SR for the muon channel, after a background-only fit to the data. The signal distributions are scaled to the cross section predicted by the theory. The hatched bands show the post-fit uncertainty band, combining all sources of uncertainty. The ratio of data to the background predictions is shown in the panels below the distributions.

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Search for single production of a vector-like T quark decaying to a top quark and a neutral scalar boson in lepton+jets final states at sqrt(s) = 13 TeV

The CMS collaboration
CMS-PAS-B2G-23-009, 2025.
Inspire Record 2922273 DOI 10.17182/hepdata.158362

A search for single production of a vector-like T quark with charge $2/3\,e$, in the decay channel with a top quark and a neutral scalar boson $\phi$ is presented. The $\phi$ boson can be a standard model Higgs boson or a new particle beyond the standard model. The top quark is identified in its leptonic decay, and the neutral boson decays into a bottom quark-antiquark pair. Final states with boosted topologies are considered and machine learning techniques are exploited for optimal classification. The analysis uses data collected by the CMS experiment in proton-proton collisions at a center-of-mass energy of $13~\mathrm{TeV}$, corresponding to an integrated luminosity of $138~\mathrm{fb}^{-1}$ recorded at the CERN LHC in 2016$-$2018. Limits at $95\%$ confidence levels are set on the product of the cross section and branching fraction for a T quark of small decay width. They are in the range between 15 and $0.15~\mathrm{fb}$, depending on T quark and $\phi$ boson masses. In the case of the decay channel with a top quark and a standard model Higgs boson, for most of the studied range the analysis provides limits which are better or comparable with previous searches performed in CMS.

19 data tables

Distribution of the mass of the AK8 jet selected as the $\phi$ boson candidate for data and simulated background events in the (TopT, XbbL) validation region for the muon channel. The distribution is shown before the final fit for signal extraction.

Distribution of the mass of the AK8 jet selected as the $\phi$ boson candidate for data and simulated background events in the (TopT, XbbL) validation region for the electron channel. The distribution is shown before the final fit for signal extraction.

Distribution of the mass of the AK8 jet selected as the $\phi$ boson candidate for data and simulated background events in the (TopL, XbbL) validation region for the muon channel. The distribution is shown before the final fit for signal extraction.

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