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Light-by-Light Scattering at Future $e^+e^-$ Colliders
/ Ellis, John (King's Coll. London ; NICPB, Tallinn ; CERN) ; Mavromatos, Nick E. (King's Coll. London ; Natl. Tech. U., Athens) ; Roloff, Philipp (CERN) ; You, Tevong (CERN ; Cambridge U., DAMTP ; Cambridge U.)
We study the sensitivity of possible CLIC and FCC-ee measurements of light-by-light scattering to old and new physics, including the Heisenberg-Euler Lagrangian in the Standard Model with possible contributions from loops of additional charged particles or magnetic monopoles, the Born-Infeld extension of QED, and effective dimension-8 operators involving four electromagnetic field strengths as could appear in the Standard Model Effective Field Theory. We find that FCC-ee measurements at 365 GeV and CLIC measurements at 350 GeV would be sensitive to new physics scales of half a TeV in the dimension-8 operator coefficients, and that CLIC measurements at 1.4 TeV or 3 TeV would be sensitive to new physics scales {$\sim 2$ TeV or 5 TeV} at 95% CL, corresponding to probing loops of new particles with masses up to $\sim 3.7$ TeV {for large charges and/or multiple species}. [...]
arXiv:2203.17111; KCL-PH-TH/2022-02; CERN-TH-2022-011.-
2022-07-23 - 26 p.
- Published in : Eur. Phys. J. C
Fulltext: document - PDF; 2203.17111 - PDF;
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Probing New Physics in Dimension-8 Neutral Gauge Couplings at $e^+e^-$ Colliders
/ Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn) ; He, Hong-Jian (Tsung-Dao Lee Inst., Shanghai ; Shanghai Jiao Tong U. ; Tsinghua U., Beijing ; Peking U., CHEP) ; Xiao, Rui-Qing (Tsung-Dao Lee Inst., Shanghai ; Shanghai Jiaotong U.)
Neutral triple gauge couplings (nTGCs) are absent in the standard model effective theory up to dimension-6 operators, but could arise from dimension-8 effective operators. In this work, we study the pure gauge operators of dimension-8 that contribute to nTGCs and are independent of the dimension-8 operator involving the Higgs doublet. [...]
arXiv:2008.04298; KCL-PH-TH/2020-28; CERN-TH-2020-076.-
2020-10-30 - 25 p.
- Published in : Sci. China Phys. Mech. Astron. 64 (2021) 221062
Fulltext: PDF;
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Constraining Gluonic Quartic Gauge Coupling Operators with $gg \to \gamma \gamma$
/ Ellis, John (CERN ; King's Coll. London ; NICPB, Tallinn) ; Ge, Shao-Feng (Tokyo U., IPMU ; UC, Berkeley)
Gluon-gluon to photon-photon scattering $gg \to \gamma\gamma$ offers to the LHC experiments a uniquely powerful probe of dimension-8 operators in the Standard Model Effective Field Theory (SMEFT) that are quadratic in both the electromagnetic and gluonic field-strength tensors, such as would appear in the Born-Infeld extension of the Standard Model (SM). We use 13-TeV ATLAS data on the production of isolated photon pairs to set lower limits on the scales of dimension-8 operators $M \gtrsim 1$~TeV, and discuss the prospective sensitivities of possible future hadron colliders..
arXiv:1802.02416; KCL-PH-TH-2018-02; CERN-TH-2018-014; IPMU-18-0022.-
2018-07-24 - 6 p.
- Published in : Phys. Rev. Lett. 121 (2018) 041801
Article from SCOAP3: PDF; Fulltext: PDF; Fulltext from Publisher: PDF;
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Hadron collider probes of the quartic couplings of gluons to the photon and $Z$ boson
/ Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn) ; Ge, Shao-Feng (Shanghai Jiaotong U. ; Tsung-Dao Lee Inst., Shanghai ; Shanghai Jiao Tong U.) ; Ma, Kai (Shanghai Jiaotong U. ; Tsung-Dao Lee Inst., Shanghai ; HIAS, UCAS, Hangzhou ; ICTP-AP, Beijing ; Shaanxi U. Tech.)
We explore the experimental sensitivities of measuring the $gg \rightarrow Z \gamma$ process at the LHC to the dimension-8 quartic couplings of gluon pairs to the $Z$ boson and photon, in addition to comparing them with the analogous sensitivities in the $gg \to \gamma \gamma$ process. These processes can both receive contributions from 4 different CP-conserving dimension-8 operators with distinct Lorentz structures that contain a pair of gluon field strengths, $\hat G^a_{\mu \nu}$, and a pair of electroweak SU(2) gauge field strengths, $W^i_{\mu \nu}$, as well as 4 similar operators containing a pair of $\hat G^a_{\mu \nu}$ and a pair of U(1) gauge field strengths, $B_{\mu \nu}$. [...]
arXiv:2112.06729; KCL-PH-TH/2021-95; CERN-TH-2021-215.-
2022-04-21 - 28 p.
- Published in : JHEP 2204 (2022) 123
Fulltext: 2112.06729 - PDF; document - PDF;
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Probing the Scale of New Physics in the $ZZ\gamma$ Coupling at $e^+e^-$ Colliders
/ Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn ; Tsung-Dao Lee Inst., Shanghai) ; Ge, Shao-Feng (Tsung-Dao Lee Inst., Shanghai ; Tokyo U., IPMU ; UC, Berkeley ; Shanghai Jiaotong U.) ; He, Hong-Jian (Tsung-Dao Lee Inst., Shanghai ; Shanghai Jiaotong U. ; Tsinghua U., Beijing ; Peking U., CHEP) ; Xiao, Rui-Qing (Tsung-Dao Lee Inst., Shanghai ; Shanghai Jiaotong U.)
The $ZZ\gamma$ triple neutral gauge couplings are absent in the Standard Model (SM) at the tree level. They receive no contributions from dimension-6 effective operators, but can arise from effective operators of dimension-8. [...]
arXiv:1902.06631; KCL-PH-TH/2019-11; CERN-TH/2019-008; CERN-TH-2019-008; IPMU19-0021.-
2020-06-09 - 32 p.
- Published in : Chin. Phys. C 44 (2020) 063106
Article from SCOAP3: PDF; Fulltext: PDF;
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Sensitivities of Prospective Future e+e- Colliders to Decoupled New Physics
/ Ellis, John (King's Coll. London ; CERN) ; You, Tevong (King's Coll. London ; Cambridge U. ; Cambridge U., DAMTP)
We explore the indirect sensitivities to decoupled new physics of prospective precision electroweak measurements, triple-gauge-coupling measurements and Higgs physics at future $e^+e^-$ colliders, with emphasis on the ILC250 and FCC-ee. The Standard Model effective field theory (SM EFT) is adopted as a model-independent approach for relating experimental precision projections to the scale of new physics, and we present prospective constraints on the Wilson coefficients of dimension-6 operators. [...]
arXiv:1510.04561; KCL-PH-TH-2015-47; LCTS-2015-35; CERN-PH-TH-2015-244; DAMTP-2015-62; CAVENDISH-HEP-15-09; KCL-PH-TH-2015-47; LCTS-2015-35; CERN-PH-TH-2015-244; CAVENDISH-HEP-15-09; DAMTP-2015-62.-
Geneva : CERN, 2016-03-14 - 19 p.
- Published in : JHEP 03 (2016) 089
Article from SCOAP3: PDF; Fulltext: PDF; Springer Open Access article: PDF; External link: Preprint
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Comparing EFT and Exact One-Loop Analyses of Non-Degenerate Stops
/ Drozd, Aleksandra (King's Coll. London) ; Ellis, John (King's Coll. London ; CERN) ; Quevillon, Jérémie (King's Coll. London) ; You, Tevong (King's Coll. London)
We develop a universal approach to the one-loop effective field theory (EFT) using the Covariant Derivative Expansion (CDE) method. We generalise previous results to include broader classes of UV models, showing how expressions previously obtained assuming degenerate heavy-particle masses can be extended to non-degenerate cases. [...]
arXiv:1504.02409; KCL-PH-TH-2015-17; LCTS-2015-08; CERN-PH-TH-2015-072; KCL-PH-TH-2015-17; LCTS-2015-08; CERN-PH-TH-2015-072.-
Geneva : CERN, 2015-06-04 - 25 p.
- Published in : JHEP 06 (2015) 028
Article from SCOAP3: PDF; Fulltext: PDF; Springer Open Access article: PDF; External link: Preprint
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10.
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The Future of High-Energy Collider Physics
/ Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn)
High-energy collider physics in the next decade will be dominated by the LHC, whose high-luminosity incarnation will take Higgs measurements and new particle searches to the next level. [...]
arXiv:1810.11263 ; KCL-PH-TH-2018-61 ; CERN-TH-2018-228.
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2018. - 15 p.
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