Dijet photoproduction at HERA and the structure of the photon.

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Krakauer, D. ; et al.
Eur.Phys.J.C 23 (2002) 615-631, 2002.
Inspire Record 568665 DOI 10.17182/hepdata.46761

The dijet cross section in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb$^{-1}$. The events were required to have a virtuality of the incoming photon, $Q^2$, of less than 1 GeV$^2$ and a photon-proton centre-of-mass energy in the range $134 < W_{\gamma p} < 277$ GeV. Each event contains at least two jets satisfying transverse-energy requirements of $E_{T}^{\rm jet1}>14$ GeV and $E_{T}^{\rm jet2}>11$ GeV and pseudorapidity requirements of $-1<\eta^{\rm jet1,2}<2.4$. The measurements are compared to next-to-leading-order QCD predictions. The data show particular sensitivity to the density of partons in the photon, allowing the validity of the current parameterisations to be tested.

24 data tables

Measured cross section as a function of COS(THETA*), where THETA* is the dijet angle in the parton-parton c.m. frame. The data are shown in two X(C=GAMMA) regions.

Measured cross section as a function of ET(JET1) for X(C=GAMMA) > 0.75 for:. -1 < ETARAP(JET1) < 0. -1 < ETARAP(JET2) < 0.

Measured cross section as a function of ET(JET1) for X(C=GAMMA) > 0.75 for:. 0 < ETARAP(JET1) < 1. -1 < ETARAP(JET2) < 0.

More…

Measurement of the neutral kaon regeneration amplitude in carbon at momenta below 1-GeV/c.

The CPLEAR collaboration Angelopoulos, A. ; Apostolakis, A. ; Aslanides, E. ; et al.
Phys.Lett.B 413 (1997) 422-430, 1997.
Inspire Record 449883 DOI 10.17182/hepdata.47397

The neutral kaon regeneration amplitude in carbon at momenta between 250 and 750 MeV/ c was determined by measuring the interference of inherent and coherently regenerated K S amplitudes. This interference appears in the rates of initially pure (tagged) K 0 and K 0 decaying to π + π − after crossing a carbon absorber.

1 data table

No description provided.


Direct determination of two-pion correlations for anti-p p --> 2pi+ 2pi- annihilation at rest.

The CPLEAR collaboration Angelopoulos, A. ; Apostolakis, A. ; Aslanides, E. ; et al.
Eur.Phys.J.C 1 (1998) 139-148, 1998.
Inspire Record 450961 DOI 10.17182/hepdata.47355

None

2 data tables

PI+ PI+ correlations. The correlation function is parametrized as follows R = 1 + CONST(NAME=BEC-LAM)*EXP(-CONST(NAME=BEC-R)**2*MQ**2), where MQ**2 = M(pi1 + pi2)**2 - 4*M(pi)**2.

PI- PI- correlations. The correlation function is parametrized as follows R = 1 + CONST(NAME=BEC-LAM)*EXP(-CONST(NAME=BEC-R)**2*MQ**2), where MQ**2 = M(pi1 + pi2)**2 - 4*M(pi)**N = RE.


First observation of a particle - anti-particle asymmetry in the decay of neutral kaons into pi0 pi0

The CPLEAR collaboration Adler, R. ; Alhalel, T. ; Angelopoulos, A. ; et al.
Z.Phys.C 70 (1996) 211-218, 1996.
Inspire Record 399741 DOI 10.17182/hepdata.48092

CP violation has been observed as a time-dependent rate asymmetry between the decays ${⩈erline K}^0 ⌝ghtarrow ≪^{0} ≪^{0}$ and K0 → π0π{0}, where the neutral kaons are produced with definite and individually known strangeness in ${⋏r p}p ⌝ghtarrow{⩈erline K}^0 K^+≪^- $ or p̅p → K0 K− π+. A special technique for the data analysis has been developed. The values obtained for ϕ00 and ¦ η00¦ are in agreement with those of previous measurements of CP violation.

1 data table

No description provided.


Measurement of K(L) - K(S) mass difference using semileptonic decays of tagged neutral kaons

The CPLEAR collaboration Adler, R. ; Alhalel, T. ; Angelopoulos, A. ; et al.
Phys.Lett.B 363 (1995) 237-242, 1995.
Inspire Record 398337 DOI 10.17182/hepdata.52370

We present a new measurement of the K L -K S mass difference ( Δm ) using semileptonic decays of neutral kaons. The measurement yields Δm = (0.5274 ± 0.0029 stat. ± 0.0005 syst. ) × 10 10 ħ/s.

1 data table

No description provided.