Measurement of the eta and eta' transition form factors at q**2 = 112-GeV**2.

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Bona, M. ; et al.
Phys.Rev.D 74 (2006) 012002, 2006.
Inspire Record 716277 DOI 10.17182/hepdata.22085

We report a study of the processes e+e- -> eta gamma and e+e- -> etaprime gamma at a center-of-mass energy of 10.58 GeV, using a 232 fb^-1 data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20+6-5 eta gamma and 50+8-7 etaprime gamma events over small backgrounds, and measure the cross sections sigma(e+e- -> eta gamma) =4.5+1.2-1.1(stat)+-0.3(sys) fb and sigma(e+e- -> etaprime gamma)=5.4+-0.8(stat)+-0.3(sys) fb. The corresponding transition form factors at q^2 = 112 GeV^2 are q^2|F_eta(q^2)|=0.229+-0.030+-0.008 GeV, and q^2|F_etaprime(q^2)|=0.251+-0.019+-0.008 GeV, respectively.

3 data tables

Measured cross sections.

Undressed cross sections calculated by applying a 7.5 +- 0.2 PCT correction for vacuum polarization.

Transition form factors at Q**2 = 112 GeV**2.


Study of the Exclusive Initial-State-Radiation Production of the DDbar System

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
SLAC-PUB-12818, 2008.
Inspire Record 776519 DOI 10.17182/hepdata.18803

A search for charmonium and other new states is performed in a study of exclusive initial-state-radiation production of D Dbar events from electron-positron annihilations at a center-of-mass energy of 10.58 GeV. The data sample corresponds to an integrated luminosity of 384 fb-1 and was recorded by the BABAR experiment at the PEP-II storage ring. The D Dbar mass spectrum shows clear evidence of the psi(3770) plus other structures near 3.9, 4.1, and 4.4 GeV/c^2. No evidence for Y(4260) -> D Dbar is observed, leading to an upper limit of B(Y(4260) -> D Dbar)/B(Y(4260) -> J/psi pi+ pi-) < 1.0 at 90 % confidence level.

1 data table

Measured cross section for D0 DBAR0 and D+ D- production. Bins with no data are shown with a 'dash'.


Measurement of the e+ e- ---> b anti-b cross section between s**(1/2) = 10.54-GeV and 11.20-GeV

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Karyotakis, Y. ; et al.
Phys.Rev.Lett. 102 (2009) 012001, 2009.
Inspire Record 797507 DOI 10.17182/hepdata.18666

We report e+e- --> b anti-b cross section measurements by the BABAR experiment performed during an energy scan in the range of 10.54 to 11.20 GeV at the PEP-II e+e- collider. A total relative error of about 5% is reached in more than three hundred center-of-mass energy steps, separated by about 5 MeV. These measurements can be used to derive precise information on the parameters of the Y(10860) and Y(11020) resonances. In particular we show that their widths may be smaller than previously measured.

1 data table

Measured values of R(b) from the detailed scan in SQRT(S),. where R(b) is the ratio between the number of observed E+ E- --> B BBAR(GAMMA) normalized to luminosity divided to the bare dimuon cross-section.


A Study of e+ e- ---> p anti-p using initial state radiation with BABAR

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Boutigny, D. ; et al.
Phys.Rev.D 73 (2006) 012005, 2006.
Inspire Record 700020 DOI 10.17182/hepdata.41831

The e+e- -> p anti-p cross section is determined over a range of p anti-p masses, from threshold to 4.5 GeV/c^2, by studying the e+e- -> p anti-p gamma process. The data set corresponds to an integrated luminosity of 232 fb^-1, collected with the BABAR detector at the PEP-II storage ring, at an e+e- center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, |G_E/G_M|, is measured for p anti-p masses below 3 GeV/c^2: its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c^2. We also measure J/psi -> p anti-p and psi(2S) -> p anti-p branching fractions and set an upper limit on Y(4260) -> p anti-p production and decay.

2 data tables

The cross section and effective form factor for E+ E- --> PBAR P.

The cross section and effective form factor for E+ E- --> PBAR P.


Observation of the Exclusive Reaction e+ e- ---> phi eta at s**(1/2) = 10.58-GeV

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 74 (2006) 111103, 2006.
Inspire Record 731865 DOI 10.17182/hepdata.52608

We report the observation of $\e^+e^-\to \phi\eta$ near $\sqrt{s}$ = 10.58 GeV with 6.5 $\sigma$ significance in the $K^+K^-\gamma\gamma$ final state in a data sample of 224 $fb^{-1}$ collected by the BaBar experiment at the PEP-II $e^+e^-$ storage rings. We measure the restricted radiation-corrected cross section to be $\sigma(\e^+e^- \to \phi \eta) =$$2.1\pm 0.4 (\mathrm{stat})\pm 0.1(\mathrm{syst}) \mathrm{fb}$ within the range $|\cos\theta^*| < 0.8$, where $\theta^*$ is the center-of-mass polar angle of the $\phi$ meson. The $\phi$ meson is required to be in the invariant mass range of 1.008 $< m_{\phi} <$ 1.035 \gevcc. The radiation-corrected cross section in the full $\cos\theta^*$ range is extrapolated to be $2.9\pm 0.5 (\mathrm{stat})\pm 0.1(\mathrm{syst}) \mathrm{fb}$.

1 data table

Radiation corrected cross section in the limited cos(theta) range and extrapolated to the full range assuming a 1+ cos(theta)**2 dependence.


Measurement of event shape variables in deep inelastic e p scattering.

The H1 collaboration Adloff, C. ; Aid, S. ; Anderson, M. ; et al.
Phys.Lett.B 406 (1997) 256-270, 1997.
Inspire Record 443753 DOI 10.17182/hepdata.23948

Deep inelastic e^+ scattering data, taken with the H1 detector at HERA, are used to study the event shape variables thrust, jet broadening and jet mass in the current hemisphere of the Breit frame over a large range of momentum transfers Q between 7 GeV and 100 GeV. The data are compared with results from e^+e^- experiments. Using second order QCD calculations and an approach to relate hadronisation effects to power corrections an analysis of the Q dependences of the means of the event shape parameters is presented, from which both the power corrections and the strong coupling constant are determined without any assumption on fragmentation models. The power corrections of all event shape variables investigated follow a 1/Q behaviour and can be described by a common parameter alpha_0.

6 data tables

The data on the differential event shape distrubutions are shown only as a illustration to show the agreement with the Lepto and pQCD calculations and contain only statistical errors. The authors are preparing another paper which details these differential distributions including full point-to-point systematics.

Usual definition of Thrust.

The same as usual thrust definition but with the thrust axis replaced by the current hemisphere axis (0,0,-1), where positive Z direction coincide with theincoming proton beam direction.

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Total photoproduction cross-section measurement at HERA energies

The H1 collaboration Ahmed, T. ; Andreev, V. ; Andrieu, B. ; et al.
Phys.Lett.B 299 (1993) 374-384, 1993.
Inspire Record 340891 DOI 10.17182/hepdata.45139

We present first results on the total photoproduction cross section measurement with the H1 detector at HERA. The data were extracted from low Q 2 collisions of 26.7 GeV electrons with 820 GeV protons. The γp total cross section has been measured by two independent methods in the γp center of mass energy range from 90 to 290 GeV. For an average center of mass energy of 195 GeV a value of σ tot ( γp ) = 159 ± 7 (stat.) ± 20 (syst.) μb was obtained.

2 data tables

Data from tagged sample.

Data from untagged sample.


Elastic and inelastic photoproduction of J / psi mesons at HERA

The H1 collaboration Aid, S. ; Andreev, V. ; Andrieu, B. ; et al.
Nucl.Phys.B 472 (1996) 3-31, 1996.
Inspire Record 416868 DOI 10.17182/hepdata.44896

Results on \jpsi\ production in $e p$ interactionsin the H1 experiment at HERA are presented. The \jpsi\ mesons are produced by almost real photons ($Q~2\approx 0$) and detected via their leptonic decays. The data have been taken in 1994 and correspond to an integrated luminosity of $2.7\,\mbox{pb}~{-1}$. The $\gamma p$ cross section for elastic \jpsi\ production is observed to increase strongly with the \cm\ energy. The cross section for diffractive $J/\psi$ production with proton dissociation is found to be of similar magnitude as the elastic cross section. Distributions of transverse momentum and decay angle are studied and found to be in accord with a diffractive production mechanism. For inelastic \jpsi\ production the total $\gamma p$ cross section, the distribution of transverse momenta, and the elasticity of the \jpsi\ are compared to NLO QCD calculations in a colour singlet model and agreement is found. Diffractive \psiprime\ production has been observed and a first estimate of the ratio to \jpsi\ production in the HERA energy regime is given.

14 data tables

J/PSI reconstructed via MU+ MU- decay mode.

J/PSI reconstructed via E+ E- decay mode.

J/PSI reconstructed via MU+ MU- decay mode.

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Photo-production of psi(2S) mesons at HERA.

The H1 collaboration Adloff, C. ; Aid, S. ; Anderson, M. ; et al.
Phys.Lett.B 421 (1998) 385-394, 1998.
Inspire Record 451266 DOI 10.17182/hepdata.44434

Quasi-elastic (z >0.95) photo-production of psi' mesons has been observed at HERA for photon-proton centre-of-mass energies in the range 40 to 160 GeV. The psi' mesons were identified through their decays to l+l- and to J/psi pi+ pi-, where the J/psi subsequently decays to l+l-, the lepton l being either a muon or an electron. The cross-section for quasi-elastic photoproduction was measured to be [18.0 +- 2.8 (stat) +- 3.0(syst)] nb at a photon-proton centre-of-mass energy of 80 GeV. The ratio of the psi' to J/psi quasi-elastic cross-sections is 0.150 +- 0.027 (stat) +- 0.022 (syst).

9 data tables

Overall value for photoproduction cross section combining the different decay modes and data sample.. 1994 and 1995 data.. The second systematic error is from the branching ratio uncertainties.

Combined cross section from PSI(3685) --> J/PSI(1S) < E+ E- > PI+ PI- and PSI(3685) --> J/PSI(1S) < MU+ MU- > PI+ PI- modes using both the 1994 and 1995 data.. The second systematic error is from the branching ratio uncertainties.

Cross section from PSI(3685) --> J/PSI(1S) < E+ E- > PI+ PI- mode.

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Multi-jet event rates in deep inelastic scattering and determination of the strong coupling constant.

The H1 collaboration Adloff, C. ; Anderson, M. ; Andreev, V. ; et al.
Eur.Phys.J.C 6 (1999) 575-585, 1999.
Inspire Record 473521 DOI 10.17182/hepdata.44216

Jet event rates in deep inelastic ep scattering at HERA are investigated applying the modified JADE jet algorithm. The analysis uses data taken with the H1 detector in 1994 and 1995. The data are corrected for detector and hadronization effects and then compared with perturbative QCD predictions using next-to-leading order calculations. The strong coupling constant alpha_S(M_Z^2) is determined evaluating the jet event rates. Values of alpha_S(Q^2) are extracted in four different bins of the negative squared momentum transfer~$\qq$ in the range from 40 GeV2 to 4000 GeV2. A combined fit of the renormalization group equation to these several alpha_S(Q^2) values results in alpha_S(M_Z^2) = 0.117+-0.003(stat)+0.009-0.013(syst)+0.006(jet algorithm).

3 data tables

Measured (2+1) jet event rates using the modified JADE algorithm (C=MEAS), corrected to the hadron (C=HAD) and to the parton (C=PAR) level. The variable Z(p) is defined as the minimum (for i=1,2) of. (E_jet,i*(1-cos(theta_jet,i)/SUM(j=1,2)(E_jet,j*(1-cos(theta,j)).

ALPHAS at different Q2 values. The TOT error is the total error.

ALPHAS extrapolated to the Z0 mass. The second DSYS (systematic) error is from the jet finding alogrithm.