Suppression of Ultra Relativistic Electron Radiation in a Thin Layer of Matter: Direct Manifestation of “Half-Bare” Particle Interaction S.P. Fomin, A.S. Fomin and N.F. Shul’ga Akhiezer Institute for Theoretical Physics National Science Center “Kharkov Institute of Physics & Technology” Kharkov 61108, Ukraine ( IC New Trends in HEP Sept 2013 BITP, Alushta, Crimea

Overview: Introduction and motivation: Bremssrahlung at ultra high energy Multiple scattering effect on radiation: LPM effect Radiation in a thin layer of matter (SLAC exp E-146) TSF effect: theory and CERN experiment NA63 Spectral-angular distribution and polarization of γ-quanta at the non-dipole regime of radiation Future experiment suggestions

3 Coherence length (Ter-Mikaelian, 1953)

1934: Bethe-Heitler theory of Bremsstrahlung 1934: Bethe-Heitler theory of Bremsstrahlung H. Bethe and W. Heitler, Proc. Roy. Soc. A 146 (1934) 83., and if where is the Radiation length = f(Z,n), but not  !!! screening effect

Coherence Length amorphous media crystal

6 Cosmic ray M.Miesowicz, O.Stanisz, W.Wolther. Novo Cimento 5 (1957) 513. experiments: A.Varfolomeev et al. Sov. Phys. JETP 11 (1960) 23. Multiple Scattering Effect on Radiation in Amorphous Medium L. Landau and Ya. Pomeranchuk Dokl. Akad. Nauk SSSR 92 (1953) 735. A.B. Migdal, Dokl. Akad. Nauk SSSR 96 (1954) 49; JETP 32 (1957) 633.

7 LPM effect for very high energy LPM effect for very high energy F(x) = E’ LPM / E’ BH x = ω/ ε Increasing of Radiation length !!! GEANT, … Detector design and Radiation shielding calculation …

8 1994: SLAC experiment E-146

9 SLAC experiment E-146 Anthony P.L. et al., Phys. Rev. Lett. 75 (1995) Klein S., Rev. Mod. Phys. 71 (1999) Bethe-Heitler ? ? ? LPM effect, but T < l c and T > l c F.F. Ternovskii. JETP 12 (1961) 123.

10 Radiation in a thin layer of matter : 1978 Shul’ga N.F. and Fomin S.P., JETP Lett. 27 (1978)126; 1986 Fomin S.P. and Shul’ga N.F., Phys. Lett. A114 (1986)148. ; suppression of radiation

E.Feinberg, JETP 50 (1966) 202. S.P. Fomin, N.F. Shul’ga, Phys. Let. A 114 (1986) 148 A.I. Akhiezer, N.F. Shul’ga, Sov.Phys.Usp. 30 (1987) 197 Electromagnetic field of electron at scattering - retarded Liénard–Wiechert potential

13 Quantitative theory of radiation in a thin layer of matter Shul'ga N.F., Fomin S.P., JETP Lett. 63 (1996) 873; JETP 86 (1998) 32; NIM B145 (1998) 73. :,

14 Other publications on this subject : R. Blankenbacler, S.D. Drell. The Landau-Pomeranchuk-Migdal effect for finite targets. Phys.Rev. 1996, v. D53, p R. Blankenbacler. Structured targets and Landau-Pomeranchuk-Migdal Effect. Phys. Rev. 1997, v. D55, p B.G. Zhakharov. Structured targets and Landau-Pomeranchuk-Migdal effect for finite-size targets.JETP Lett. 1996, v. 64, p B.G. Zhakharov. Light-cone path integral approach to the Landau-Pomeranchuk-Migdal effect.Yadernaya Fiz. 1998, v. 61, p R.Baier, Yu.L.Dokshitser, A.H.Mueller, S.Peigne, D.Schiff. The Landau-Pomeranchuk- Migdal effect in QED.Nucl. Phys. 1996, v. B478, p V.N. Baier, V.M. Katkov. Landau-Pomeranchuk-Migdal effect and transition radiation in structured targets.Phys. Rev. 1999, v. D60, , 12 p.....

A.I. Akhiezer, N.F. Shul'ga, S.P. Fomin. The Landau-Pomeranchuk-Migdal Effect. Cambridge Scientific Publishers, Cambridge, UK, 2005, 215 p.

16 CERN NA63 experiment 2005 SPS secondary positron beam E = 178 GeV, target thickness: 2, 10, 20 μm

CERN NA63 experiment 2008 SPS secondary electron beam E = 206 & 234 GeV, target thickness: 5-10 μm

18 CERN NA63 experiment 2008

19 Thickness dependence !!! N. Shul'ga, S. Fomin: JETP Lett. 27(1978)126. Phys.Let.A 114(1986)148; JETP 86(1998)32  1 = 800 MeV  2 = 350 MeV  3 = 150 MeV  TSF = m 2 t / 2 ≈ 6.6 PeV ∙ t (сm)  TSF ≈ 2  2 /t If  <<  TSF : t ≈ l c (  )

June 5, 2009 Dear Nikolai and Serguei, It is a pleasure for me to tell you that in the CERN experiment we are we have confirmed the logarithmic thickness running these days, we have confirmed the logarithmic thickness dependence that your theory for thin targets has predicted dependence that your theory for thin targets has predicted, … … we are certain that the effect is there, and we thought we would let you we have 'seen' the 'half-bare' electron :-) know that we have 'seen' the 'half-bare' electron :-) Best regards from all of us at NA63, Ulrik Uggerhoj Spokesman of CERN NA63 collaboration Professor, Aarhus University, Denmark CERN experiment NA63 - June 2009

21 TSF Theory & CERN experiment NA63 June 2009 A.S.Fomin, S.P.Fomin, N.F.Sul’ga, Nuovo Cimento 34C (2011) 45. H.D.Thomsen et al., Phys. Rev. D 81 (2010)

BH, LPM and TSF theories applicability ranges Thickness dependence of radiation spectral density The cover picture from H.Thomsen PhD thesises

23 Angular Dirtribution of Radiation in Non-Dipole Case S.P. Fomin, N.F. Shul’ga, S.N. Shul’ga, Phys. Atom. Nucl. 66 (2003) 421

24 Fomin S.P., Shul’ga N.F., Shul’ga S.N., Yad.Fiz. 66 (2003) 421 Angular Dirtribution of Radiation in Non-Dipole Case θ y = 0 :,

Spectral-angular distribution of radiation in a thin amorphous target Spectral-angular distribution of radiation in a thin amorphous target Fomin S.P., Shul'ga N.F. and Shul'ga S.N., Phys. of Atomic Nuclei 66 (2003) 396.

Angular distribution of radiation in a thin amorphous target

27 Polarization matrix: Linear polarization: Circular polarization: for all observation angles ! where Polarization of Radiation at Non-Dipole Regime A.S. Fomin, S.P. Fomin, N.F. Shul'ga, Proc. SPIE, 5974 (2005) 177; 6634 (2007)

Multiple Scattering in Aligned Crystal

E e = 200 GeV W T = 20 μm ψ = ψ L   L = 35 Pc ~ 80% Electrons Polarization Polarization at Strong Non-Dipole Regime of Radiation A.S. Fomin, S.P. Fomin, N.F. Shul'ga, Proc. SPIE, 5974 (2005) 177; 6634 (2007)

Polarization in Crystalline and Amorphous Targets

Thank you for attention! Conclusion 1. 1.The effect of suppression of ultrarelativistic electron radiation due to a multiple scattering on atoms in a thin amorphous target (TSF effect) was finally confirmed in the CERN experiment NA63 by observation of logarithmic dependence of the radiation spectral density on the target thickness It is theoretically shown that this effect leads to essential changing not only spectral density of radiation, but also its angular distribution and polarization, that can be verified by future experiments in SLAC and CERN The TSF effect takes place also in a thin crystal at the coherent multiple scattering of an electron on the crystal atomic chains. This effect is planed for experimental study in CERN after SPS restart The analogous of the LPM and TSF effects have to take place in QCD at quark-gluon interaction.

CERN experiment NA63 (2005) CERN experiment NA63 (2005) Results of our calculations:

34 LPM and TSF effects in a crystal Shul’ga N., Fomin S., JETP Letters 27 (1978)126; Phys. Lett. A114 (1986)148. Laskin N., Mazmanishvili A., Shul’ga N., Phys. Lett. A112 (1985) 240. Multiple scattering on crystal atomic strings Shul’ga N., Truten’ V., Fomin S., J. Techn. Phys. 52 (1982) 2279.

35 CERN experiment: Bak J.F. et al. Nucl. Phys., B302 (1988) 525. Theory: Laskin N., Shul’ga N., Phys.Lett. A135 (1989) 147. e - : E=10 GeV e + : E=20 GeV

Lapko V.P., Nasonov N.N., NIM B 84 (1994) 48. Circular Polarization of Radiation in Non-Dipole Case

How relativistic electron emits photon? How relativistic electron emits photon? Force lines at rest and uniformly moving electric charge B.Bolotovsky and A. Serov, Sov. Phys. Usp. 179 (2009) 517.

R.Y. Tsien, AJP 40 (1972) 46 How relativistic electron emits photon? How relativistic electron emits photon? The own Coulomb fields of instantly started and immediately stopped charge

Как излучает релятивистский электрон? Как излучает релятивистский электрон? Поле вращающегося заряда с тангенсиальной скоростью  = 0.5 и  = 0.9 R.Y. Tsien, AJP 40 (1972) 46

Как излучает релятивистский электрон? Как излучает релятивистский электрон? Поле вращающегося заряда с тангенсиальной скоростью  = 0.95 и поле рассеянного на угол 5° заряда с  = R.Y. Tsien, AJP 40 (1972) 46

Как излучает релятивистский электрон? Как излучает релятивистский электрон? Поле дважды рассеянного заряда

42 CERN experiment NA63 June 2009 H.D.Thomsen et al.,“The distorted Coulomb field of the scattered electron” Phys. Rev. D 81 (2010) SPS secondary electron beam E = 149 GeV, Ta target thickness: μm; Ta target thickness: μm; hω = 0.2 – 3 GeV

43 TSF Theory & CERN experiment NA63 June 2009 Thickness dependence of radiation spectral density

Coherence Length (informal introduction) pre-wave zone wave zone