Spin rotation parameters A and R for pi+ p and pi- p elastic scattering from 427-MeV/c to 657-MeV/c

Supek, I. ; Barlow, D.B. ; Briscoe, W.J. ; et al.
Phys.Rev.D 47 (1993) 1762-1775, 1993.
Inspire Record 362062 DOI 10.17182/hepdata.22623

The spin-rotation parameters A and R and the related spin-rotation angle β have been measured for π+p and π−p elastic scattering using protons polarized in the scattering plane. The pion-beam momenta are 427, 471, 547, 625, and 657 MeV/c and the angular range is −0.9≤cosΘc.m.≤0.3. The scattered pion and recoil proton were detected in coincidence, using a scintillator hodoscope for the pions, and the Large Acceptance Spectrometer combined with the JANUS polarimeter for the recoil protons. The results are compared with the four recent πN partial wave analyses (PWA's). Our data show that the major features of these PWA's are correct. The A and R measurements complete our program of pion-nucleon experiments, providing full data sets at three of the above beam momenta. Such sets can be used to test the constraints in the PWA's or to obtain a model-independent set of πN scattering amplitudes.

10 data tables

BETA is the spin-rotation angle.

BETA is the spin-rotation angle.

BETA is the spin-rotation angle.

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Investigation of nuclear charge symmetry by pion elastic scattering from H-3 and He-3

Dhuga, K.S. ; Berman, B.L. ; Briscoe, W.J. ; et al.
Phys.Rev.C 54 (1996) 2823-2830, 1996.
Inspire Record 433024 DOI 10.17182/hepdata.25746

We have measured differential cross sections for pion elastic scattering from H3 and He3 in the angular region near the minimum in the non-spin-flip amplitude. Data were acquired for incident pion energies of 180, 220, 256, and 295 MeV. Nuclear charge symmetry is investigated with the aid of several charge-symmetric ratios formed from combinations of measured cross sections. A particularly intriguing result is obtained from the superratio R, which is defined as R=dσ(π+3H)dσ(π−3H)/dσ(π+3He)dσ(π−3He). R is found to be greater than unity at 180 MeV and significantly smaller than unity at 256 MeV, with the transition occurring at around 210 MeV. The charge-symmetry prediction for this ratio (after allowance for the Coulomb force) is one, and is independent of energy and angle. © 1996 The American Physical Society.

8 data tables

Axis error includes +- 3/3 contribution.

Axis error includes +- 3/3 contribution.

Axis error includes +- 3/3 contribution.

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He-3 and He-4 production by 800-MeV protons from C-12, Ti, and Pb at forward angles

Barlow, D.B. ; Nefkens, B.M.K. ; Pillai, C. ; et al.
Phys.Rev.C 45 (1992) 293-298, 1992.
Inspire Record 337057 DOI 10.17182/hepdata.26108

The doubly differential cross section for the production of He3 and He4 by 800 MeV protons from C12, Ti, and Pb has been measured at laboratory angles of 6° and 15°. The momentum of the detected helium nuclei varied from 1 to 2 GeV/c, the maximum being well above the incident proton momentum of 1.46 GeV/c. The cross sections were found to increase with increasing target mass and decrease with increasing momentum and scattering angle. In our momentum region, the He3 production cross section is 1.5–10 times larger than He4 depending on the target and the momentum. The data are consistent with the hypothesis that the dominant reaction mechanism is a direct process where the initial nucleon-nucleon scattering is followed by a sequential pickup of neutrons.

8 data tables

No description provided.

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Recoil Proton Polarization in $\pi P$ Elastic Scattering at 547-{MeV}/c and 625-{MeV}/c

Seftor, C.J. ; Adrian, S.D. ; Briscoe, W.J. ; et al.
Phys.Rev.D 39 (1989) 2457-2463, 1989.
Inspire Record 282265 DOI 10.17182/hepdata.23234

The polarization of the recoil proton in π+p and π−p elastic scattering using a liquid-hydrogen target has been measured for backward angles at 547 and 625 MeV/c. The scattered pion and recoil proton were detected in coincidence using the large-acceptance spectrometer to detect and analyze the momentum of the pions and the JANUS polarimeter to identify and measure the polarization of the protons. Results from this experiment agree with other measurements of the recoil polarization, with analyzing-power data previously taken by this group, and with predictions of partial-wave analyses.

4 data tables

No description provided.

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PRODUCTION OF HIGH MOMENTUM NEGATIVE PIONS BY 800-MEV PROTONS AT 0-DEGREES TO 20-DEGREES

Barlow, D.B. ; Nefkens, B.M.K. ; Pillai, C.T. ; et al.
Nucl.Instrum.Meth.A 271 (1988) 471-474, 1988.
Inspire Record 270458 DOI 10.17182/hepdata.37244

The π − yield in the momentum range 500–740 MeV/ c produced by 800 MeV protons incident on targets of Be and C has been measured at laboratory production angles between 0° and 20°. The yield of 725 MeV/ c π − from Be and C at 0° is a factor of 6 greater than at 20°, for 600 MeV/ c π − the factor is 3. The yield from beryllium is typically 30% higher than from carbon.

2 data tables

No description provided.

No description provided.


Elastic scattering of pions from H-3 and He-3 into the backward hemisphere

Matthews, S.K. ; Briscoe, W.J. ; Bennhold, C. ; et al.
Phys.Rev.C 51 (1995) 2534-2541, 1995.
Inspire Record 405001 DOI 10.17182/hepdata.25941

We have measured differential cross sections for the elastic scattering of charged pions from H3 and He3 into the backward hemisphere. Near the peak of the delta resonance, at Tπ=180 MeV, an angular distribution covering 114° to 168° in the laboratory extends our earlier measurements. At Tπ=142, 180, 220, and 256 MeV, we have measured an excitation function at angles approaching 170°. The cross sections for the reactions He3(π+,π+)3He, H3(π−,π−)3H show a rise at back angles which is not seen for He3(π−,π−)3He and H3(π+,π+)3H. There is a dip in the cross sections near 130° for Tπ=180 MeV.

4 data tables

No description provided.

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Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle

The Belle collaboration Wang, X.L. ; Yuan, C.Z. ; Shen, C.P. ; et al.
Phys.Rev.Lett. 99 (2007) 142002, 2007.
Inspire Record 756643 DOI 10.17182/hepdata.51373

The cross section for e+e- to pi+ pi- psi(2S) between threshold and \sqrt{s}=5.5 GeV is measured using 673 fb^{-1} of data on and off the \Upsilon(4S) resonance collected with the Belle detector at KEKB. Two resonant structures are observed in the pi+ pi- psi(2S) invariant mass distribution, one at 4361\pm 9\pm 9 MeV/c2 with a width of 74\pm 15\pm 10 MeV/c2, and another at 4664\pm 11\pm 5 MeV/c2 with a width of 48\pm 15\pm 3 MeV/c2, if the mass spectrum is parameterized with the coherent sum of two Breit-Wigner functions. These values do not match those of any of the known charmonium states.

1 data table

Measured cross section.


Observation of a near-threshold enhancement in the $e^+e^- \to \Lambda_c^+ \Lambda_c^-$ cross section using initial-state radiation

The Belle collaboration Pakhlova, G. ; Adachi, I. ; Aihara, H. ; et al.
Phys.Rev.Lett. 101 (2008) 172001, 2008.
Inspire Record 791660 DOI 10.17182/hepdata.21861

We report a measurement of the exclusive \$e^+e^- \to \Lambda_c^+ \Lambda_c^-$ cross section as a function of center-of-mass energy near the $\Lambda_c^+ \Lambda_c^-$ threshold. A clear peak with a significance of $8.8\sigma$ is observed in the $\Lambda_c^+ \Lambda_c^-$ invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of $M=(4634^{+8}_{-7} \mathrm{(stat.)} ^{+5}_{-8} \mathrm{(sys.)})\mevc$ and $\Gamma_{\mathrm{tot}}=(92^{+40}_{-24} \mathrm{(stat.)}^{+10}_{-21} \mathrm{(sys.)})\mev$ are determined. The analysis is based on a study of events with initial-state-radiation photons in a data sample collected with the Belle detector at the $\Upsilon(4S)$ resonance and nearby continuum with an integrated luminosity of 695 $\mathrm{fb}^{-1}$ at the KEKB asymmetric-energy $e^+e^_$ collider.

1 data table

Cross section for the exclusive process E+ E- --> LAMBDA/C+ LAMBDA/CBAR-.


Search for quark compositeness, axigluons and heavy particles using the dijet invariant mass spectrum observed in p anti-p collisions

The CDF collaboration Abe, F. ; Albrow, Michael G. ; Akimoto, H. ; et al.
Phys.Rev.Lett. 71 (1993) 2542-2546, 1993.
Inspire Record 356676 DOI 10.17182/hepdata.19713

The dijet invariant mass distribution has been measured in the region between 140 and 1000 GeV/c2, in 1.8 TeV p p¯ collisions. Data collected with the Collider Detector at Fermilab show agreement with QCD calculations. A limit on quark compositeness of Λc>1.3 TeV is obtained. Axigluons with masses between 240 and 640 GeV/c2 are excluded at 95% C.L. if we assume ten open decay channels. Model-independent limits on the production of heavy particles decaying into two jets are also presented.

1 data table

No description provided.


Search for excited quarks in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Albrow, Michael G. ; Amidei, Dante E. ; et al.
Phys.Rev.Lett. 72 (1994) 3004-3008, 1994.
Inspire Record 360332 DOI 10.17182/hepdata.42507

If quarks are composite particles then excited states are expected. We have searched in pp¯ collisions for excited quarks (q*) which decay to common quarks by emitting a W boson (q*→qW) or a photon (q*→qγ). The simplest model of excited quarks has been excluded for mass M*<540 GeV/c2 at 95% confidence level.

3 data tables

No description provided.

No description provided.

No description provided.