BabaYaga Event Generator Home Page

BabaYaga is a Monte Carlo event generator for e⁺e^- --> e⁺e^-, μ⁺μ^-, γγ and π⁺π^- processes at flavour factories, i.e. for energies below 10-12 GeV. It includes the relevant QED radiative corrections in the QED Parton Shower approach.
It has been developed at the INFN, Sezione di Pavia, and Dipartimento di Fisica Nucleare e Teorica of the Università degli Studi di Pavia (Italy). The current authors of the code are C.M. Carloni Calame, G. Montagna, O. Nicrosini, F. Piccinini (notice the anti-spam [at] in the e-mail addresses!).
Recently it has been matched with exact fixed order calculations.
BabaYaga is now released in two versions, BabaYaga@NLO, more recent, and BabaYaga 3.5. BabaYaga@NLO does not still simulate π⁺π^- pair production, nevertheless it allows to study the production of a dark matter U boson (massive photon) decaying in e⁺e^-, μ⁺μ^- pairs.
Please stay tuned at this page for updates of the generator.

We would be very grateful to you if you could send an e-mail to one of the authors after downloading the generator, so that we can inform you about updates of the code, publications, etc.

We would be also very grateful to you if you could cite the following papers when referring to BabaYaga:
[1] G. Balossini, C.M. Carloni Calame, G. Montagna, O. Nicrosini and F. Piccinini, "Matching perturbative and Parton Shower corrections to Bhabha process at flavour factories", Nucl. Phys. B758, 227-253, 2006, [hep-ph/0607181]
[2] G. Balossini, C. Bignamini, C.M. Carloni Calame, G. Montagna, F. Piccinini and O. Nicrosini, "Photon pair production at flavour factories with per mille accuracy", Phys. Lett. B663, 209-313, 2008, [0801.3360 [hep-ph]]
[3] C.M. Carloni Calame, G. Montagna, O. Nicrosini, F. Piccinini, Nucl. Phys. Proc. Suppl. 131, 48-55, 2004 [hep-ph/0312014]
[4] C.M. Carloni Calame, Phys. Lett. B520, 16-24, 2001 [hep-ph/0103117]
[5] C.M. Carloni Calame, C. Lunardini, G. Montagna, O. Nicrosini, F. Piccinini, Nucl. Phys. B584, 459-479, 2000 [hep-ph/0003268]

If you use BABAYAGA for dark matter studies, please cite also:
[6] L. Barzè, G. Balossini, C. Bignamini, C.M. Carloni Calame, G. Montagna, O. Nicrosini, F. Piccinini, "Radiative Events as a Probe of Dark Forces at GeV-Scale e⁺e^- Colliders", submitted to Phys Rev. D, [1007.4984 [hep-ph]].

BabaYaga@NLO

This version is a complete rewriting of the generator, which now could also simulate the production of a single dark matter massive photon decaying in e⁺e^-, μ⁺μ^- pairs. The code includes also non-log order alpha corrections, which were the main source of theoretical error in the previous releases of the code. Download it here and please refer to the README file in the package for its usage.
The theoretical error of the new release is estimated to be around 0.1%, for Standard Model processes.
In the papers [1], [2] and [6], where the theoretical formulation, numerical results and comparisons to independent calculations are presented, you can find more details about the theoretical accuracy estimate of the generator.

BabaYaga 3.5

This version of the generator can be used for e⁺e^-, μ⁺μ^-, γγ and π⁺π^- final states. The radiative corrections are here included in a pure Parton Shower approach, even though it has been improved to include initial-final state radiation interference for a more accurate description of radiative events. The estimated theoretical accuracies for the different channels are

· Bhabha  0.5%   (superseded by BabaYaga@NLO)
· μ⁺μ^-            1%
· γγ                1%
· π⁺π^-           1%   (notice that for this channel only initial state radiation is accounted for)

Download it here and please refer to the README file in the package for its usage.