New measurement of the rare decay $\eta \to \pi^0\gamma\gamma$ with the Crystal Ball/TAPS detectors at the Mainz Microtron

The A2 at MAMI collaboration Nefkens, B.M.K. ; Prakhov, S. ; Aguar-Bartolome, P. ; et al.
Phys.Rev. C90 (2014) 025206, 2014.
Inspire Record 1297221 DOI 10.17182/hepdata.64169
1 data table

D(WIDTH(ETA --> PI0 GAMMA GAMMA))/DM**2(GAMMA GAMMA) obtained from the data of 2007 and 2009 and their average. The error on the average is the total error.


Measurement of the $\gamma p \to K^{0} \Sigma^{+}$ reaction with the Crystal Ball/TAPS detectors at the Mainz Microtron

The A2 collaboration Aguar-Bartolome, P. ; Annand, J.R.M. ; Arends, H.J. ; et al.
Phys.Rev. C88 (2013) 044601, 2013.
Inspire Record 1237227 DOI 10.17182/hepdata.64391

The γp→K0Σ+ reaction has been measured from threshold to Eγ=1.45 GeV (WCM=1.9 GeV) using the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. In the present experiment, this reaction was searched for in the 3π0p final state, by assuming KS0→π0π0 and Σ+→π0p. The experimental results include total and differential cross sections as well as the polarization of the recoil hyperon. The new data significantly improve empirical knowledge about the γp→K0Σ+ reaction in the measured energy range. The results are compared to previous measurements and model predictions. It is demonstrated that adding the present γp→K0Σ+ results to existing data allowed a better description of this reaction with various models.

4 data tables

The differential cross section for photon energies 1125, 1175 and 1225 MeV.

The differential cross section for photon energies 1275, 1325, 1375 and 1425 MeV.

The recoil polarization of the SIGMA+ for photon energy 1125, 1175 and 1225 MeV.

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Measurement of $3pi^0$ photoproduction on the proton from threshold to 1.4 GeV

Starostin, A. ; Suarez, I.M. ; Nefkens, B.M.K. ; et al.
2011.
Inspire Record 884723 DOI 10.17182/hepdata.57591
1 data table

The measured total cross section with statistical errors.


Study of the $\gamma p -> \eta p$ reaction with the Crystal Ball detector at the Mainz Microtron(MAMI-C)

The Crystal Ball at MAMI collaboration McNicoll, E.F. ; Prakhov, S. ; Strakovsky, I.I. ; et al.
Phys.Rev. C82 (2010) 035208, 2010.
Inspire Record 860725 DOI 10.17182/hepdata.56733

The gp-->etap reaction has been measured with the Crystal Ball and TAPS multiphoton spectrometers in the energy range from the production threshold of 707 MeV to 1.4 GeV (1.49 =< W >= 1.87 GeV). Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz Microtron MAMI-C and momentum analyzed by the Glasgow Tagging Spectrometer were used for the eta-meson production. Our accumulation of 3.8 x 10^6 gp-->etap-->3pi0p-->6gp events allows a detailed study of the reaction dynamics. The gp-->etap differential cross sections were determined for 120 energy bins and the full range of the production angles. Our data show a dip near W = 1680 MeV in the total cross section caused by a substantial dip in eta production at forward angles. The data are compared to predictions of previous SAID and MAID partial-wave analyses and to thelatest SAID and MAID fits that have included our data.

121 data tables

Total cross section for the reaction GAMMA P --> ETA P.

Differential cross section for the reaction GAMMA P --> ETA P at a photon energy of 710.4 MeV. The errors in the table are statistical only and there is an overall systematic uncertainty of 4.3 PCT.

Differential cross section for the reaction GAMMA P --> ETA P at a photon energy of 714.5 MeV. The errors in the table are statistical only and there is an overall systematic uncertainty of 4.3 PCT.

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Radiative pi0 photoproduction on protons in the Delta+(1232) region

Schumann, S. ; Boillat, B. ; Downie, E.J. ; et al.
Eur.Phys.J. A43 (2010) 269-282, 2010.
Inspire Record 843314 DOI 10.17182/hepdata.54377

The reaction gamma p -> p pi0 gamma' has been measured with the Crystal Ball / TAPS detectors using the energy-tagged photon beam at the electron accelerator facility MAMI-B. Energy and angular differential cross sections for the emitted photon gamma' and angular differential cross sections for the pi0 have been determined with high statistics in the energy range of the Delta+(1232) resonance. Cross sections and the ratio of the cross section to the non-radiative process gamma p -> p pi0 are compared to theoretical reaction models, having the anomalous magnetic moment kappa_Delta+ as free parameter. As the shape of the experimental distributions is not reproduced in detail by the model calculations, currently no extraction of kappa_Delta+ is feasible.

17 data tables

Total cross section for the background reaction GAMMA P --> P PI0.

Total cross section for the background reaction GAMMA P --> P PI0 PI0.

Angular distribution of the PI0 in the reaction GAMMA P --> P PI0 at beam energy 400 MeV. Inclusive measurement where only the PI0 decay photons are detected.

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Measurement of K- p radiative capture to gamma Lambda and gamma Sigma0 for p(K-) between 514 and 750 MeV/c

Prakhov, S. ; Vancraeyveld, P. ; Phaisangittisakul, N. ; et al.
Phys.Rev. C82 (2010) 015201, 2010.
Inspire Record 839376 DOI 10.17182/hepdata.55317

Differential cross sections for $K^-$ radiative capture in flight on the proton, leading to the $\gamma\Lambda$ and $\gamma\Sigma^0$ final states, have been measured at eight $K^-$ momenta between 514 and 750 MeV/$c$. The data were obtained with the Crystal Ball multiphoton spectrometer installed at the separated $K/\pi$ beam line C6 of the BNL Alternating Gradient Synchrotron. The results substantially improve the existing experimental data available for studying radiative decays of excited hyperon states. An exploratory theoretical analysis is performed within the Regge-plus-resonance approach. According to this analysis, the $\gamma\Sigma^0$ final state is dominated by hyperonresonance exchange and hints at an important role for a resonance in the mass region of 1700 MeV. In the $\gamma\Lambda$ final state, on the other hand, the resonant contributions account for only half the strength, and the data suggest the importance of a resonance in the mass region of 1550 MeV.

7 data tables

Differential cross section for the K- P --> GAMMA LAMBDA reaction at thelower beam momenta.

Differential cross section for the K- P --> GAMMA LAMBDA reaction at thehigher beam momenta.

Differential cross section for the K- P --> GAMMA SIGMA0 reaction at thelower beam momenta.

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Photoproduction of pi0 eta on protons and the Delta(1700)D(33) resonance

The Crystal Ball at MAMI & TAPS & A2 collaborations Kashevarov, V.L. ; Fix, A. ; Aguar-Bartolome, P. ; et al.
Eur.Phys.J. A42 (2009) 141-149, 2009.
Inspire Record 811783 DOI 10.17182/hepdata.52974
5 data tables

Total cross section for the GAMMA P --> PI0 ETA P reaction.. Statistical erros only.

The differential cross section as a function of cos(theta(pi0) in the canonical(K) reference frame.. Statistical erros only.

The differential cross section as a function of phi(pi0) in the canonical(K) reference frame.. Statistical erros only.

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Measurement of pi0 Lambda, anti-K0 n, and pi0 Sigma0 production in K- p interactions for p(K-) between 514 and 750-MeV/c

Prakhov, S. ; Nefkens, B.M.K. ; Bekrenev, V. ; et al.
Phys.Rev. C80 (2009) 025204, 2009.
Inspire Record 804864 DOI 10.17182/hepdata.52376

The results on the differential cross sections as well as the polarizations of $\Lambda$ and $\Sigma^0$ have been obtained for $\bar{K}^0 n$, $\pi^0 \Lambda$, and $\pi^0 \Sigma^0$ production in $K^- p$ interactions at eight $K^-$ momenta between 514 and 750 MeV/$c$. The study is conducted by measuring multiphoton final states with the Crystal Ball spectrometer, using a $K^-$ beam from the Alternating Gradient Synchrotron of BNL. The results improve substantially the existing data, allowing a detailed reexamination of the $\Lambda^*$ and $\Sigma^*$ states in our energy range.

11 data tables

Differential cross section for the K- P --> KBAR0 N reaction. Errors are statistical only.

Differential cross section for the K- P --> KBAR0 N reaction. Errors are statistical only.

Differential cross section for the K- P --> PI0 LAMBDA reaction. Errors are statistical only.

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Measurement of pi- p ---> pi0 n in the vicinity of the eta threshold

Starostin, A. ; Prakhov, S. ; Nefkens, B.M.K. ; et al.
Phys.Rev. C72 (2005) 015205, 2005.
Inspire Record 688197 DOI 10.17182/hepdata.25171
9 data tables

Differential cross section for incident pion momentum 649, 654 and 657 MeV.

Differential cross section for incident pion momentum 661, 666 and 669 MeV.

Differential cross section for incident pion momentum 673, 678 and 681 MeV.

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Measurement of pi- p ---> eta n from threshold to p (pi-) = 747-MeV/c

Prakhov, S. ; Nefkens, B.M.K. ; Allgower, C.E. ; et al.
Phys.Rev. C72 (2005) 015203, 2005.
Inspire Record 687736 DOI 10.17182/hepdata.25215
3 data tables

Total cross sections.

Differential cross section for the 4 lowest beam momenta.

Differential cross section for the 3 highest beam momenta.


K- p ---> pi0 pi0 sigma0 at p(K)- = 514-MeV/c to 750-MeV/c mev and comparison with other pi0 pi0 production

The Crystall Ball collaboration Prakhov, S. ; Nefkens, B.M.K. ; Allgower, C.E. ; et al.
Phys.Rev. C70 (2004) 034605, 2004.
Inspire Record 659770 DOI 10.17182/hepdata.25227
1 data table

Total cross section measurement. Statistical errors only.


Exclusive photoproduction of the cascade (Xi) hyperons

The CLAS collaboration Price, J.W. ; Nefkens, B.M.K. ; Ducote, J.L. ; et al.
Phys.Rev. C71 (2005) 058201, 2005.
Inspire Record 660705 DOI 10.17182/hepdata.25222

We report on the first measurement of exclusive Xi-(1321) hyperon photoproduction in gamma p --> K+ K+ Xi- for 3.2 < E(gamma) < 3.9 GeV. The final state is identified by the missing mass in p(gamma,K+ K+)X measured with the CLAS detector at Jefferson Laboratory. We have detected a significant number of the ground-state Xi-(1321)1/2+, and have estimated the total cross section for its production. We have also observed the first excited state Xi-(1530)3/2+. Photoproduction provides a copious source of Xi's. We discuss the possibilities of a search for the recently proposed Xi5-- and Xi5+ pentaquarks.

1 data table

Cross section averaged over the energy range 3.2 to 3.9 GeV.


Reaction K- p ---> pi0 pi0 lambda from pK- = 514-MeV/c to 750-MeV/c

Prakhov, S. ; Nefkens, B.M.K. ; Allgower, C.E. ; et al.
Phys.Rev. C69 (2004) 042202, 2004.
Inspire Record 650074 DOI 10.17182/hepdata.25228
5 data tables

Measured cross section. Statistical errors only.

Differential cross section for the di-pion system in the c.m. system for incident momenta 514 to 629 MeV.

Differential cross section for the di-pion system in the c.m. system for incident momenta 659 to 750 MeV.

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Measurement of pi- p ---> pi0 pi0 n from threshold to p(pi-) 750-MeV/c

The Crystal Ball collaboration Prakhov, S. ; Nefkens, B.M.K. ; Allgower, C.E. ; et al.
Phys.Rev. C69 (2004) 045202, 2004.
Inspire Record 647544 DOI 10.17182/hepdata.25355
5 data tables

Measured total cross section. Statistical errors only.

Differential angular distributions of the 2PI0 system for the LH2 data at beam momenta 355 to 472 MeV/c. Statistical errors only.

Differential angular distributions of the 2PI0 system for the LH2 data at beam momenta 550 to 678 MeV/c. Statistical errors only.

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Differential cross-section of the charge exchange reaction pi- p ---> pi0 n in the momentum range from 148-MeV/c to 323-MeV/c

The Crystal Ball collaboration Sadler, M.E. ; Kulbardis, A. ; Abaev, V. ; et al.
Phys.Rev. C69 (2004) 055206, 2004.
Inspire Record 646714 DOI 10.17182/hepdata.31725

Measured values of the differential cross section for pion-nucleon charge exchange are presented at momenta 148, 174, 188, 212, 238, 271, 298, and 323 MeV/c, a region dominated by the Delta resonance. Complete angular distributions were obtained using the Crystal Ball detector at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). Statistical uncertainties of the differential cross sections are typically 2-6%, exceptions being the results at the lowest momentum and at the most forward measurements of the five lowest momenta. We estimate the systematic uncertainties to be 3-6%.

3 data tables

The errors shown are statistical only.

The errors shown are statistical only.

The total charge-exchange reaction cross section as a function of pion momentum obtained by integrating the differential cross sections. The errors shown are the total and statistical errors.


Measurement of the pi- p ---> 3 pi0 n total cross-section from threshold to 0.75-GeV/c

Starostin, A. ; Nefkens, B.M.K. ; Manley, D.M. ; et al.
Phys.Rev. C67 (2003) 068201, 2003.
Inspire Record 620818 DOI 10.17182/hepdata.25279
1 data table

Total cross section from threshold to 750 MeV. Only statistical errors are given in the table.


Measurement of K- p --> eta Lambda near threshold

The Crystal Ball collaboration Starostin, A. ; Nefkens, B.M.K. ; Berger, E. ; et al.
Phys.Rev. C64 (2001) 055205, 2001.
Inspire Record 569202 DOI 10.17182/hepdata.25269
5 data tables

Total cross section measurement for K- P --> ETA LAMBDA. Errors shown are statistical only.

Differential cross sections DSIG/DOMEGA for K- P --> ETA LAMBDA. Errors shown are statistical only.

Differential cross sections DSIG/DOMEGA for K- P --> ETA LAMBDA. Errors shown are statistical only.

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The Reaction d (polarized) p ---> He-3 pi0 near threshold

Nikulin, V.N. ; Boudard, A. ; Clajus, M. ; et al.
Phys.Rev. C54 (1996) 1732-1740, 1996.
Inspire Record 421018 DOI 10.17182/hepdata.25833
1 data table

No description provided.


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. C54 (1996) 2823-2830, 1996.
Inspire Record 433024 DOI 10.17182/hepdata.25746
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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The Reactions p d ---> He-3 eta and p d ---> He-3 pi+ pi- near the eta threshold

Mayer, B. ; Boudard, A. ; Fabbro, B. ; et al.
Phys.Rev. C53 (1996) 2068-2074, 1996.
Inspire Record 404168 DOI 10.17182/hepdata.25834

The reaction pd→3Heη has been studied with the SPES2 spectrometer, for proton energies between 0.2 MeV and 11 MeV above threshold. The total cross section rises from 0.25 to 0.40 μb in this region. The observed energy dependence can be attributed to the strong final state interaction. The angular distribution is nearly isotropic, consistent with S wave production. A measurement of the pd→3Heπ+π− cross section in the threshold region is also presented. The setup, which is capable of producing 105 tagged η/s with only a few percent background, is used to investigate rare η decays. © 1996 The American Physical Society.

1 data table

Threshold energy = 891.37 MeV.


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. C51 (1995) 2534-2541, 1995.
Inspire Record 405001 DOI 10.17182/hepdata.25941
4 data tables

No description provided.

No description provided.

No description provided.

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eta meson photoproduction on hydrogen near threshold

Price, J.W. ; Anton, G. ; Arends, J. ; et al.
Phys.Rev. C51 (1995) R2283-R2287, 1995.
Inspire Record 405009 DOI 10.17182/hepdata.25882
1 data table

No description provided.


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. D47 (1993) 1762-1775, 1993.
Inspire Record 362062 DOI 10.17182/hepdata.22623
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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Total cross-section of the p p ---> p p eta reaction near threshold

Bergdolt, A.M. ; Bergdolt, G. ; Bing, O. ; et al.
Phys.Rev. D48 (1993) R2969-R2973, 1993.
Inspire Record 364575 DOI 10.17182/hepdata.22579
1 data table

No description provided.


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. C45 (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.

No description provided.

No description provided.

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