BABAR measurement of baryon time-like form factors via initial state radiation

Baldini Ferroli

doi:10.1088/1674-1137/34/6/040

Chinese Physics C> 2010, Vol. 34> Issue(6) : 860-862 DOI: 10.1088/1674-1137/34/6/040

BABAR measurement of baryon time-like form factors via initial state radiation

Baldini Ferroli ^,

¹ Enrico Fermi Center, Rome, Italy² INFN, Laboratori Nazionali di Frascati, Frascati, Italy

Abstract
HTML
Reference
Related

PDF

Abstract：
BABAR has measured with unprecedented accuracy the e⁺e^－→pp and e⁺e^－→ΛΛ cross sections by means of the initial state radiation technique, which has the advantages of good efficiency, good energy resolution and full angular acceptance, even exactly at threshold. A peculiar feature of these cross sections is their non-vanishing values at threshold. In the case of charged baryons, this phenomenon is expected according to the Coulomb interaction between the outgoing baryon and antibaryon. Once this Coulomb enhancement factor is taken into account, the striking result is achieved that the proton form factor at threshold is |G^p(4 M²_p)| = 1, that is what is expected for pointlike fermion pairs, in spite of the proton structure. However a Coulomb enhancement factor is not expected for neutral fermions, likely in contradiction with the BABAR data. Qualitatively this behaviour is consistent with Coulomb interactions at the valence quark level.

References

[1]

. Baldini R, Pacetti S, Zallo A, Zichichi A. Eur. Phys. J A,2009, 39: 3152. Aubert B et al (BABAR collaboration). Phys. Rev. D,2006, 73: 0120053. Aubert B et al (BABAR collaboration). arXiv:0709.1988[hep-ex]4. Sakharov A D. Zh. Eksp. Teor. Fiz., 1948, 18: 631[Sov. Phys. Usp., 1991, 34: 375]; Sommerfeld A. In:Atombau und Spektralliniem. Vieweg, Braunschweig. 1944;Schwinger J. In: Particles, Sources, and Fields5. Baldini R, Pacetti S, Zallo A. arXiv: 0812.3283v26. Pacetti S. Eur. Phys. J. A, 2007, 32: 4217. Brodsky S J et al. Phys. Lett. B, 1995, 359: 355 [arXiv:hep-ph/9508274]; Castellani G et al. arXiv:hep-ph/0509089 andreferences therein

[1]	Liang-Liang Liu , Chao Wang , Xin-Heng Guo . Electromagnetic form factors of Λ_c in the space-like momentum region. Chinese Physics C, 2018, 42(10): 103106. doi: 10.1088/1674-1137/42/10/103106
[2]	Han Guo , Zi-Ping Zhang . A method for measuring D^* electromagnetic form factors in e⁺ e^- annihilation. Chinese Physics C, 2017, 41(9): 093001. doi: 10.1088/1674-1137/41/9/093001
[3]	Fangcheng He , Ping Wang . Dirac and Pauli form factors of nucleons using nonlocal chiral effective Lagrangian. Chinese Physics C, 2017, 41(11): 114106. doi: 10.1088/1674-1137/41/11/114106
[4]	Bao-dong Sun , Yu-bing Dong . Deuteron electromagnetic form factors with the light-front approach. Chinese Physics C, 2017, 41(1): 013102. doi: 10.1088/1674-1137/41/1/013102
[5]	WU Qing , ZHOU Li-Juan , XIANG Qian-Fei , MA Wei-Xing . Multiquark cluster form factors in the relativistic harmonic oscillator model. Chinese Physics C, 2015, 39(1): 013102. doi: 10.1088/1674-1137/39/1/013102
[6]	LIANG Cui-Ying , DONG Yu-Bing . Deuteron form factors in a phenomenological approach. Chinese Physics C, 2015, 39(10): 104104. doi: 10.1088/1674-1137/39/10/104104
[7]	WU Xing-Gang , HUANG Tao , ZHONG Tao . Information on the pion distribution amplitude from the pion-photon transition form factor with the Belle and BABAR data. Chinese Physics C, 2013, 37(6): 063105. doi: 10.1088/1674-1137/37/6/063105
[8]	JIN Dan , YANG Ya-Dong . Space- and time-like kaon electromagnetic form factors in perturbative QCD. Chinese Physics C, 2012, 36(10): 941-946. doi: 10.1088/1674-1137/36/10/004
[9]	DONG Yu-Bing . An estimate of two-photon exchange effect on deuteron electromagnetic form factors. Chinese Physics C, 2010, 34(9): 1346-1349. doi: 10.1088/1674-1137/34/9/039
[10]	V. P. Druzhinin . Measurements of the γγ^→π⁰ and γγ^→η_c transition form factors at BABAR. Chinese Physics C, 2010, 34(6): 816-821. doi: 10.1088/1674-1137/34/6/033
[11]	S. Pacetti¹ , 2 . Nucleon form factors: the space-time connection. Chinese Physics C, 2010, 34(6): 874-876.
[12]	ZHOU Hai-Qing . Two-photon-exchange contribution to proton form factors in both space-like and time-like regions. Chinese Physics C, 2010, 34(6): 869-873. doi: 10.1088/1674-1137/34/6/042
[13]	WANG Wen-Feng (for the BABAR collaboration) . Precise measurement of the e⁺e^－→π⁺π^－(γ) cross section with the initial state radiation method at BABAR. Chinese Physics C, 2010, 34(6): 692-697. doi: 10.1088/1674-1137/34/6/014
[14]	WANG Mei-Juan , LIU Lian-Shou , WU Yuan-Fang . Trace initial interaction from final state observable in relativistic heavy ion collisions. Chinese Physics C, 2009, 33(1): 36-41. doi: 10.1088/1674-1137/33/1/008
[15]	A. J. Buchmann . Excited nucleon electromagnetic form factors from broken spin-flavor symmetry. Chinese Physics C, 2009, 33(12): 1257-1260. doi: 10.1088/1674-1137/33/12/034
[16]	R. W. Gothe . Nucleon transition form factors at JLab: status and outlook. Chinese Physics C, 2009, 33(12): 1216-1221. doi: 10.1088/1674-1137/33/12/026
[17]	CHEN Dian-Yong , ZHOU Hai-Qing , DONG Yu-Bing . Two-photon exchange to proton electromagnetic properties in time-like region. Chinese Physics C, 2009, 33(12): 1336-1339. doi: 10.1088/1674-1137/33/12/049
[18]	M. Sudol (for \=PANDA collaboration) . Time-like proton form factor measurement with PANDA. Chinese Physics C, 2009, 33(12): 1244-1248. doi: 10.1088/1674-1137/33/12/031
[19]	LIU Yan-Ping , CHEN Zhao-Yang , BA Wei-Zhen , FAN Yan-Wei , DU Yan-Zhao , PAN Shi-Lie , GUO Qi . A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence. Chinese Physics C, 2008, 32(5): 381-384. doi: 10.1088/1674-1137/32/5/011
[20]	Qin Keyu , Jiang Huanqing , Liu Bo . Initial-State Interaction and J/ψ Suppression in High-Energy Proton-Nucleus Collisions. Chinese Physics C, 1996, 20(S4): 359-362.

Access

Get Citation

Baldini Ferroli. BABAR measurement of baryon time-like form factors via initial state radiation[J]. Chinese Physics C, 2010, 34(6): 860-862. doi: 10.1088/1674-1137/34/6/040

Baldini Ferroli. BABAR measurement of baryon time-like form factors via initial state radiation[J]. Chinese Physics C, 2010, 34(6): 860-862. doi: 10.1088/1674-1137/34/6/040 shu

RIS(for EndNote,Reference Manager,ProCite)

BibTex

Txt

Milestone

Received: 2010-02-05
Revised: 1900-01-01

Article Metric

Article Views(2578)
PDF Downloads(429)
Cited by(0)

Policy on re-use

To reuse of subscription content published by CPC, the users need to request permission from CPC, unless the content was published under an Open Access license which automatically permits that type of reuse.

通讯作者: 陈斌, bchen63@163.com

1.
沈阳化工大学材料科学与工程学院沈阳 110142

BABAR measurement of baryon time-like form factors via initial state radiation

Corresponding author: Baldini Ferroli,

¹ Enrico Fermi Center, Rome, Italy² INFN, Laboratori Nazionali di Frascati, Frascati, Italy

Received Date: 2010-02-05

Accepted Date: 1900-01-01

Available Online: 2010-06-05

Abstract:

BABAR has measured with unprecedented accuracy the e⁺e^－→pp and e⁺e^－→ΛΛ cross sections by means of the initial state radiation technique, which has the advantages of good efficiency, good energy resolution and full angular acceptance, even exactly at threshold. A peculiar feature of these cross sections is their non-vanishing values at threshold. In the case of charged baryons, this phenomenon is expected according to the Coulomb interaction between the outgoing baryon and antibaryon. Once this Coulomb enhancement factor is taken into account, the striking result is achieved that the proton form factor at threshold is |G^p(4 M²_p)| = 1, that is what is expected for pointlike fermion pairs, in spite of the proton structure. However a Coulomb enhancement factor is not expected for neutral fermions, likely in contradiction with the BABAR data. Qualitatively this behaviour is consistent with Coulomb interactions at the valence quark level.

HTML

Reference (1)

BABAR measurement of baryon time-like form factors via initial state radiation

Abstract：

References

Access

Article Metrics

Metrics

通讯作者: 陈斌, bchen63@163.com

Email This Article