Untitled

Abstract

It is known that for any 2-to-2 process in MSSM, only the helicity conserving (HC) amplitudes survive asymptotically. Studying many such processes, at the 1-loop Electroweak (EW) order, it is found that their high energy HC amplitudes are determined by just three forms: a log-squared function of the ratio of two of the (s, t, u) variables, to which a π 2 is added; and two Sudakov-like ln-and ln 2 -terms accompanied by respective massdependent constants. Apart from a possible additional residual constant (which is also discussed), these HC amplitudes, may be expressed as linear combinations of the above three forms, with coefficients being rational functions of the (s, t, u) variables. This 1-loop property, called supersimplicity, is of course claimed for the 2-to-2 processes considered; but no violating examples are known at present. For ug → dW , supersimplicity is found to be a very good approximation at LHC energies, provided the SUSY scale is not too high. SM processes are also discussed, and their differences are explored.

Specific supersimple properties ofe−e+→γHat high energy

“…For e − e + → γH though, the additional augmented quadratic Sudakov logarithms though, are different from those in [5,13,15]. The forms we meet here are…”

“…Particularly because e − e + → γH is determined by the helicity violating (HV) amplitudes 1 at high energies, in contrast to the processes aforementioned in the preceding paragraph, which are dominated by their helicity conserving (HC) amplitudes [16,17]. As we show in the Appendix, one consequence of this is that the augmented Sudakovtype quadratic logarithms in e − e + → γH do not retain the universal structure observed in (gg → γγ, γZ, ZZ, W − W + ), ug → dW + , (e − e + → tt, W − W + , ZH), [13,14,15,5]. This way, we have calculated various polarized and unpolarized cross sections and asymmetries, and studied their sensitivity to the underlying dynamics.…”

“…These consist of the linear log augmented Sudakov form and the forms involving ratios of Mandelstam variables, as in [5,13,15]. These are…”

“…From their expansions at high energy [12], we then establish simple approximate expressions called supersimple (sim), as in the other similar recent studies on (gg → γγ, γZ, ZZ, W − W + ), ug → dW + and (e − e + → tt, W − W + , ZH), [13,14,15,5]. As before, we expect that these simple expressions will be useful for making quick estimates of the amplitudes and meaningful comparisons with experimental results.…”

Supersimple analysis ofe−e+→ZHat high energy

“…We have called these expressions "supersimple" (sim) and we have already derived them for e − e + → tt, e − e + → W − W + and other processes [5,6,7,8,9]. In all cases, these simple expressions can help distinguishing SM or MSSM, from other BSM (beyond the standard model) dynamics.…”