Probe anomalous tqγ couplings through single top photoproduction at the LHC

In this work we study the constraints on the anomalous tqγ   (q=u,cq=u,c) couplings by photon-produced leading single top production and single top jet associated production through the main reactions pp→pγp→pt→pW(→ℓνℓ)b+Xpp→pγp→pt→pW(→ℓνℓ)b+X and pp→pγp→ptj→pW(→ℓνℓ)bj+Xpp→pγp→ptj→pW(→ℓνℓ)bj+X assuming a typical LHC multipurpose forward detectors in a model independent effective lagrangian approach. Our results show that: for the typical detector acceptance 0.0015<ξ1<0.50.0015<ξ1<0.5, 0.1<ξ2<0.50.1<ξ2<0.5 and 0.0015<ξ3<0.150.0015<ξ3<0.15 with a luminosity of 2 fb−12 fb−1, the lower bounds of κtqγκtqγ through leading single top channel (single top jet channel) are 0.0130 (0.0156), 0.0218 (0.0206) and 0.0133 (0.01655), respectively, corresponding to Br(t→qγ)∼3×10−5Br(t→qγ)∼3×10−5. With a luminosity of 200 fb−1200 fb−1, the lower bounds of κtqγκtqγ are 0.0041 (0.0048), 0.0069 (0.0064) and 0.0042 (0.0051), respectively, corresponding to Br(t→qγ)∼4×10−6Br(t→qγ)∼4×10−6. We conclude that both channels can be used to detect such anomalous tqγ   couplings and the detection sensitivity on κtqγκtqγ is obtained.