An Improved Calculation of the Multiphoton Bremsstrahlung Process in the Presence of a Laser Beam

1977 ◽  
Vol 30 (1) ◽  
pp. 33
Author(s):  
Rama Acharya ◽  
Man Mohan

It has been noted previously that analyses of free-free transitions in the presence of an ion are appreciably affected by neglecting the Coulomb field of the ion at infinity. We have therefore made here an improved calculation of the cross section for the multiphoton bremsstrahlung process by taking account of the Coulomb field in the initial and final states.

1968 ◽  
Vol 46 (10) ◽  
pp. S377-S380 ◽  
Author(s):  
A. A. Petrukhin ◽  
V. V. Shestakov

The cross section for the muon bremsstrahlung process is calculated as a function of the nuclear form factor in the Born approximation following the Bethe and Heitler theory. The influence of the nuclear form factor is greater than that taken by Christy and Kusaka. The simple analytical expression for the effect of the screening of the atomic electrons is found. The influence of a decrease in the cross section upon the interpretation of some experimental results is estimated.


2012 ◽  
Vol 27 (14) ◽  
pp. 1230014
Author(s):  
XUEBING BU

The recent D0 results on Wγ and Zγ production are presented. First, the cross-section and the difference in rapidities between photons and charged leptons for inclusive W(→lν)+γ production in eγ and μγ final states are discussed, then are the cross-section and differential cross-section as a function of photon transverse momentum for Zγ→l+l-(l = e, μ) process. Finally, I present the limits on anomalous WWγ, ZZγ and Zγγ couplings.


2019 ◽  
Vol 127 (11) ◽  
pp. 851
Author(s):  
А.М. Райцин

The necessary conditions for the correct measurement of the width and angle of divergence of the laser beam are determined taking into account the finite dimensions of the aperture of the emitter by a method based on the determination of initial spatial moments. It is shown that in this case stringent conditions are imposed on the shape of the spatial intensity distribution in the cross section of the laser beam, which were not taken into account in the corresponding developed standards.


An expression for the cross-section describing electron capture by protons in atomic hydrogen is derived from an expansion based on atomic wave functions. Full account is taken of momentum transfer and of the non-orthogonality of the wave functions of the initial and final states by the method due to Bates. The cross-sections have been computed for proton energies from 100 to 1 MeV. In the low energy limit, the results agree with the p.s.s. calculations of Dalgarno & Yadav and in the high energy limit with the calculations of Brinkm an & Kramers.


In this paper we calculate the second Born approximation contribution to the Bremsstrahlung cross-section differential in both the photon and electron angles. This is divergent if a Coulomb potential is considered, but it is found, on following the idea of Dalitz (1951), that all observable quantities turn out to be finite when we perform the calculation for a Yukawa potential and take the limit of zero screening. It is shown that this is true to order Z 3 in the differential cross-section before it is averaged over spins, and the cross-section is calculated explicitly for the case of an unpolarized beam when the final states of polarization are not observed. Further, it is pointed out that the same methods can be applied satisfactorily in the case of pair production.


2001 ◽  
Vol 16 (supp01a) ◽  
pp. 333-335
Author(s):  
WOLFGANG LIEBIG

In this paper preliminary results of the cross-section ratio [Formula: see text] and the forward-backward asymmetry [Formula: see text] are presented for [Formula: see text] final states produced in the reaction [Formula: see text]. They are measured with the DELPHI detector at LEP collision energies ranging from 183 up to a maximum of 209 GeV. Lifetime and secondary vertex information provided by DELPHI's 3-layer microvertex detector are the main ingredients of a tagging variable which is used to separate the quark flavours. High purity selections are made from which Rf and [Formula: see text] are measured. The compatibility of the results with the Standard Model expectations is evaluated.


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