HEPData Search

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Second generation leptoquark search in p anti-p collisions at S**(1/2) = 1.8-TeV

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.

Phys.Rev.Lett. 75 (1995) 3618-3623, 1995.

Inspire Record 397099 DOI 10.17182/hepdata.42373

We report on a search for second generation leptoquarks with the D\O\ detector at the Fermilab Tevatron $p\overline{p}$ collider at $\sqrt{s}$ = 1.8 TeV. This search is based on 12.7 pb$~{-1}$ of data. Second generation leptoquarks are assumed to be produced in pairs and to decay into a muon and quark with branching ratio $\beta$ or to neutrino and quark with branching ratio $(1-\beta)$. We obtain cross section times branching ratio limits as a function of leptoquark mass and set a lower limit on the leptoquark mass of 111 GeV/c$~{2}$ for $\beta = 1 $ and 89 GeV/c$~{2}$ for $\beta = 0.5 $ at the 95\%\ confidence level.

1 data table

Table 1

The cross section times branching ratios.

rivet Analysis
Transverse energy distributions within jets in p anti-p collisions at S**(1/2) = 1.8-Tev

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.

Phys.Lett.B 357 (1995) 500-508, 1995.

Inspire Record 398175 DOI 10.17182/hepdata.42372

The distribution of the transverse energy in jets has been measured in p p collisions at s =1.8 TeV TeV using the DØ detector at Fermilab. This measurement of the jet shape is made as a function of jet transverse energy in both the central and forward rapidity regions. Jets are shown to narrow both with increasing transverse energy and with increasing rapidity. Next-to-leading order partonic QCD calculations are compared to the data. Although the calculations qualitatively describe the data, they are shown to be very dependent on renormalization scale, parton clustering algorithm, and jet direction definition and they fail to describe the data in all regions consistently.

6 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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rivet Analysis
Observation of a narrow state decaying into Xi(c)+ pi-

The CLEO collaboration Avery, P. ; Freyberger, A. ; Lingel, K. ; et al.

Phys.Rev.Lett. 75 (1995) 4364-4368, 1995.

Inspire Record 397770 DOI 10.17182/hepdata.47270

Using data recorded by the CLEO-II detector at CESR, we report the first observation of a narrow state decaying into $\Xi_c~+\pi~-$. The state has mass difference $M(\Xi_c~+\pi~-)-M(\Xi_c~+)$ of $178.2\pm0.5\pm1.0$ $\rm{MeV/c~2}$, and a width of $<5.5$ $\rm{MeV/c~2}$ (90\% confidence level limit). The most likely explanation of this new state is that it is the $J=\32$ spin excitation of the $\Xi_c~0$ charmed baryon.

1 data table

Table 1

No description provided.

Observation of the Cabibbo suppressed charmed baryon decay lambda(c)+ ---> p phi

The CLEO collaboration Alexander, J.P. ; Bebek, C. ; Berger, B.E. ; et al.

Phys.Rev.D 53 (1996) 1013-1017, 1996.

Inspire Record 397665 DOI 10.17182/hepdata.47234

We report the observation of the Cabibbo-suppressed decays \lcpkk\ and \lcpphi\ using data collected with the CLEO II detector at CESR. The latter mode, observed for the first time with significant statistics, is of interest as a test of color-suppression in charm decays. We have determined the branching ratios for these modes relative to \lcpkpi\ and compared our results with theory.

1 data table

Table 1

Branching ratio of Cabibbo-suppressed and resolved modes.

Measurement of the effective b quark fragmentation function at the Z resonance

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.

Phys.Lett.B 357 (1995) 699-714, 1995.

Inspire Record 398319 DOI 10.17182/hepdata.48137

Using a sample of about 1.46 million hadronic Z decays collected between 1991 and 1993 with the ALEPH detector at LEP, the energy distribution of the B 0 and B ± mesons produced at the Z resonance is measured by reconstructing semileptonic decays B → ℓ ν ℓ D(X) or B → ℓν ℓ D ∗+ (X) . The charmed mesons are reconstructed through the decay modes D 0 → K − π + , D 0 → K − π + π − π + , D + → K − π + π + and D ∗+ → D 0 π + . The neutrino energy is estimated from the missing energy in the lepton hemisphere. Accounting for B ∗ and B ∗∗ production, the shape of the scaled energy distribution x E (b) for mesons containing a b quark is compared to the predictions of different fragmentation models. The mean value of x E (b) is found to be 〈 x E (b) 〉 = 0.715 ± 0.007(stat) ± 0.013(syst).

1 data table

Table 1

SIG/SIG(C=ALL-X-INTERVAL) is fraction of events in bin. Third and fourth systematic errors are due to variation of D** and B** contributions respectively (model dependent, see text).

rivet Analysis
Delta++ production in hadronic Z0 decays

The OPAL collaboration Alexander, G. ; Allison, John ; Altekamp, N. ; et al.

Phys.Lett.B 358 (1995) 162-172, 1995.

Inspire Record 398320 DOI 10.17182/hepdata.48153

The production of Δ ++ baryons has been measured using 3.5 million hadronic Z 0 decays collected with the OPAL detector at LEP. The production rate and fragmentation function are presented. A total of 0.22 ± 0.04 ± 0.04 Δ ++ + ( Δ ) −− per hadronic Z 0 decay is observed. The fragmentation function is found to be softer than that predicted by the JETSET and HERWIG Monte Carlo event generators. With this measurement of Δ ++ production, at least one baryon of each strangeness level in the lightest baryon decuplet has now been measured at LEP.

1 data table

Table 1

No description provided.

Study of prompt photon production in hadronic Z0 decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Z.Phys.C 69 (1995) 1-14, 1995.

Inspire Record 397391 DOI 10.17182/hepdata.48136

None

3 data tables

Table 1

Rates for gamma + 1 jet.

Table 2

Rates for gamma + 2 jet.

Table 3

Rates for gamma + 3 jet.

A Measurement of the tau leptonic branching fractions

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Phys.Lett.B 357 (1995) 715-724, 1995.

Inspire Record 398321 DOI 10.17182/hepdata.48138

A sample of 25000 Z 0 → τ + τ − events collected by the DELPHI experiment at LEP in 1991 and 1992 is used to measure the leptonic branching fractions of the τ lepton. The results are B(τ → eν ν ) = (17.51 ± 0.39) % and B(τ → μν ν ) = (17.02 ± 0.31) %. The ratio of the muon and electron couplings to the weak charged current is measured to be g μ g e = 1.000 ± 0.013 , satisfying e-μ universality. The leptonic branching fraction corrected to the value for a massless lepton, assuming e-μ universality, is found to be B(τ → lν ν ) = (17.50 ± 0.25) %.

3 data tables

Table 1

Axis error includes +- 0.23/0.23 contribution (Data statistics).

Table 2

Axis error includes +- 0.19/0.19 contribution (Data statistics).

Table 3

Combined from the two branching fractions above. E-MU universality assumed.

Inclusive production of neutral vector mesons in hadronic Z decays

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.

Z.Phys.C 69 (1996) 379-392, 1996.

Inspire Record 398317 DOI 10.17182/hepdata.48152

Data on the inclusive production of the neutral vector mesonsρ 0(770),ω(782), K*0(892), andφ(1020) in hadronic Z decays recorded with the ALEPH detector at LEP are presented and compared to Monte Carlo model predictions. Bose-Einstein effects are found to be important in extracting a reliable value for theρ 0 production rate. An averageρ 0 multiplicity of 1.45±0.21 per event is obtained. Theω is detected via its three pion decay modeω→π + π − π 0 and has a total rate of 1.07±0.14 per event. The multiplicity of the K*0 is 0.83±0.09, whilst that of theφ is 0.122±0.009, both measured using their charged decay modes. The measurements provide information on the relative production rates of vector and pseudoscalar mesons, as well as on the relative probabilities for the production of hadrons containing u, d, and s quarks.

8 data tables

Table 1

No description provided.

Table 2

Average multiplicity per hadronic event. Extrapolation to the full X range.

Table 3

No description provided.