A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA
A search for new bosons possessing couplings to lepton-quark pairs is performed in the H1 experiment at HERA using 1994 to 1997 data corresponding to an integrated luminosity of 37 pb-1. First generation leptoquarks (LQs) are searched in very high Q2 neutral (NC) and charged (CC) current data sample...
| Egile Nagusiak: | , , , , , , , , , , , , , , , , , , , , , , , , |
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| Formatua: | Journal article |
| Hizkuntza: | English |
| Argitaratua: |
1999
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| _version_ | 1826304187357462528 |
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| author | Adloff, C Andreev, V Andrieu, B Arkadov, V Astvatsatourov, A Ayyaz, I Babaev, A Bahr, J Baranov, P Barrelet, E Bartel, W Bassler, U Bate, P Beglarian, A Behnke, O Behrend, H Beier, C Belousov, A Berger, C Bernardi, G Berndt, T Bertrand-Coremans, G Biddulph, P Bizot, J Boudry, V |
| author_facet | Adloff, C Andreev, V Andrieu, B Arkadov, V Astvatsatourov, A Ayyaz, I Babaev, A Bahr, J Baranov, P Barrelet, E Bartel, W Bassler, U Bate, P Beglarian, A Behnke, O Behrend, H Beier, C Belousov, A Berger, C Bernardi, G Berndt, T Bertrand-Coremans, G Biddulph, P Bizot, J Boudry, V |
| author_sort | Adloff, C |
| collection | OXFORD |
| description | A search for new bosons possessing couplings to lepton-quark pairs is performed in the H1 experiment at HERA using 1994 to 1997 data corresponding to an integrated luminosity of 37 pb-1. First generation leptoquarks (LQs) are searched in very high Q2 neutral (NC) and charged (CC) current data samples. The measurements are compared to Standard Model (SM) expectations from deep-inelastic scattering (DIS). A deviation in the Q2 spectrum previously observed in the 1994 to 1996 dataset at Q2≳15000GeV2 remains, though with less significance. This deviation corresponded to a clustering in the invariant mass spectrum at M ≃ 200 GeV which is not observed with the 1997 dataset alone. The NC DIS data is used to constrain the Yukawa couplings λ of first generation scalar and vector LQs in the Buchmüller-Rückl-Wyler effective model. Scalar LQs are excluded for masses up to 275 GeV for a coupling of electromagnetic strength, λ = 0.3. A sensitivity to coupling values ≲ 1 is established for masses up to 400 GeV for any LQ type. The NC and CC DIS data are combined to constrain λ for arbitrary branching ratios of the LQ into eq in a generic model. For a decay branching ratio into e+u pairs as small as 10%, LQ masses up to 260 GeV are ruled out for λ = 0.3. LQs possessing couplings to mixed fermion generations, which could lead to signals of lepton flavor violation (LFV), are searched in events with a high transverse momentum μ or τ. No μ, + X or τ + X event candidate is found that is compatible with LQ kinematics. Constraints are set on the Yukawa coupling involving the μ and τ lepton in a yet unexplored mass range. |
| first_indexed | 2024-03-07T06:13:59Z |
| format | Journal article |
| id | oxford-uuid:f07bd055-ecc9-4b7c-8855-a2faa55650ea |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:13:59Z |
| publishDate | 1999 |
| record_format | dspace |
| spelling | oxford-uuid:f07bd055-ecc9-4b7c-8855-a2faa55650ea2022-03-27T11:48:18ZA search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERAJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f07bd055-ecc9-4b7c-8855-a2faa55650eaEnglishSymplectic Elements at Oxford1999Adloff, CAndreev, VAndrieu, BArkadov, VAstvatsatourov, AAyyaz, IBabaev, ABahr, JBaranov, PBarrelet, EBartel, WBassler, UBate, PBeglarian, ABehnke, OBehrend, HBeier, CBelousov, ABerger, CBernardi, GBerndt, TBertrand-Coremans, GBiddulph, PBizot, JBoudry, VA search for new bosons possessing couplings to lepton-quark pairs is performed in the H1 experiment at HERA using 1994 to 1997 data corresponding to an integrated luminosity of 37 pb-1. First generation leptoquarks (LQs) are searched in very high Q2 neutral (NC) and charged (CC) current data samples. The measurements are compared to Standard Model (SM) expectations from deep-inelastic scattering (DIS). A deviation in the Q2 spectrum previously observed in the 1994 to 1996 dataset at Q2≳15000GeV2 remains, though with less significance. This deviation corresponded to a clustering in the invariant mass spectrum at M ≃ 200 GeV which is not observed with the 1997 dataset alone. The NC DIS data is used to constrain the Yukawa couplings λ of first generation scalar and vector LQs in the Buchmüller-Rückl-Wyler effective model. Scalar LQs are excluded for masses up to 275 GeV for a coupling of electromagnetic strength, λ = 0.3. A sensitivity to coupling values ≲ 1 is established for masses up to 400 GeV for any LQ type. The NC and CC DIS data are combined to constrain λ for arbitrary branching ratios of the LQ into eq in a generic model. For a decay branching ratio into e+u pairs as small as 10%, LQ masses up to 260 GeV are ruled out for λ = 0.3. LQs possessing couplings to mixed fermion generations, which could lead to signals of lepton flavor violation (LFV), are searched in events with a high transverse momentum μ or τ. No μ, + X or τ + X event candidate is found that is compatible with LQ kinematics. Constraints are set on the Yukawa coupling involving the μ and τ lepton in a yet unexplored mass range. |
| spellingShingle | Adloff, C Andreev, V Andrieu, B Arkadov, V Astvatsatourov, A Ayyaz, I Babaev, A Bahr, J Baranov, P Barrelet, E Bartel, W Bassler, U Bate, P Beglarian, A Behnke, O Behrend, H Beier, C Belousov, A Berger, C Bernardi, G Berndt, T Bertrand-Coremans, G Biddulph, P Bizot, J Boudry, V A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA |
| title | A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA |
| title_full | A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA |
| title_fullStr | A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA |
| title_full_unstemmed | A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA |
| title_short | A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA |
| title_sort | search for leptoquark bosons and lepton flavor violation in e p collisions at hera |
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