5 | | models available here: |
6 | | https://drive.google.com/drive/folders/1iHJWJKGd-nLOTpUqzbwlCULex2mQhNm1?usp=drive_link |
| 2 | |
| 3 | '''Description of the UFO models for HECO pair production'''[[BR]] |
| 4 | |
| 5 | |
| 6 | High-Electric-Charge Objects (HECOs) can be pair-produced via Drell-Yan and photon-fusion processes. Due to the large coupling, the perturbation theory breaks down. Nevertheless, one can resum the QED corrections at a UV fixed point for high electric charge and mass values.[[BR]] |
| 7 | The UFO models provided here describe both Photon Fusion and Drell-Yan processes, by including such resummation effects for ''spin-1/2'' HECOs with electric charge ''q > 11e''. By incorporating the resummation effects into the UFO models, we are able to provide reliable predictions for the production mechanisms under study. |
| 8 | More details on the resummation technique can be found in https://arxiv.org/pdf/2310.17452.pdf |
| 9 | |
| 10 | |
| 11 | Two distinct models have been developed:[[BR]] |
| 12 | |
| 13 | 1. γ exchange UFO model: It takes into account the sole contribution from γ exchange, which is suitable for simulating both DY and PF processes. [[BR]] |
| 14 | |
| 15 | 2. γ/Z0 exchange UFO model: This model includes the additional exchange of the Z0 boson in DY production. [[BR]] |
| 16 | |
| 17 | |
| 18 | The UFO models incorporate two new input parameters:[[BR]] |
| 19 | |
| 20 | • The multiplicity of the charge '''n''' which appears in the coupling definition g = ne, with e being the electron charge [[BR]] |
| 21 | |
| 22 | • The cutoff energy scale parameter '''lambda'''[[BR]] |
| 23 | These parameters will define the value of the running HECO mass. |
| 24 | |
| 25 | |
| 26 | |
| 27 | '''Commands for MadGraph5_aMC@NLO |
| 28 | ''' |
| 29 | |
| 30 | 1. γ-only exchange |
| 31 | |
| 32 | • Drell-Yan |
| 33 | |
| 34 | {{{ |
| 35 | import model heco_spinhalf_photononly |
| 36 | generate p p > heco heco~ |
| 37 | output DY_HECO |
| 38 | }}} |
| 39 | |
| 40 | • Photon-Fusion |
| 41 | |
| 42 | {{{ |
| 43 | import model heco_spinhalf_photononly |
| 44 | generate a a > heco heco~ |
| 45 | output PF_HECO |
| 46 | }}} |
| 47 | |
| 48 | 2. γ/Z0 exchange |
| 49 | |
| 50 | • Drell-Yan |
| 51 | |
| 52 | {{{ |
| 53 | import model heco_spinhalf_withZ0 |
| 54 | generate p p > heco heco~ |
| 55 | output DY_HECO_Z0 |
| 56 | }}} |
| 57 | |
| 58 | |
| 59 | Set run card and parameters |
| 60 | |
| 61 | |
| 62 | {{{ |
| 63 | launch name_of_theoutput ### replace name_of_theoutput accordingly, i.e. DY_HECO_Z0 |
| 64 | set ebeam1 6500 ### beam 1 energy in GeV |
| 65 | set ebeam2 6500 ### beam 2 energy in GeV |
| 66 | set lpp1 1 ### beam 1 type (1=proton) |
| 67 | set lpp2 1 ### beam 2 type (1=proton) |
| 68 | set pdlabel lhapdf ### set the pdlabel argument |
| 69 | set lhaid 82000 ### set the pdf set |
| 70 | set nevents 10000 ### number of events |
| 71 | |
| 72 | set n 20 ### set the multiplicity of the charge |
| 73 | set lambda 1000 ### set the cutoff energy scale in GeV |
| 74 | |
| 75 | }}} |
| 76 | |
| 77 | |
| 78 | |
| 79 | |