Anomaly Cancellation with an Extra Gauge Boson

Allanach, B. C.; Gripaios, Ben; Tooby-Smith, Joseph

doi:10.1103/physrevlett.125.161601

Cited by 32 publications

(49 citation statements)

References 10 publications

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“…However, the Z in [48] is but one of many extra U(1) gauge fields arising from an underlying dynamics of intersecting D-branes, with a very different set of fermion charges that is determined by the underlying brane geometry in a distinctly 'top-down' fashion. The anomalous Z that we propose in this paper is motivated rather from the bottom-up, 3 The lower limit of 1 TeV charged fermions corresponds to Yukawa couplings of 10 −1 .…”

Section: Jhep08(2021)101mentioning

confidence: 95%

“…This anomalous Z model, in contrast to its anomaly-free counterparts, necessarily features a pair of long-lived charged fermions whose masses are tied to the scale of U(1) X breaking; in particular, their masses naturally lie between 1 and 30 TeV. 3 In sections 5 and 6 we turn to the issue of fermion masses. Beyond the renormalisable third family Yukawa couplings, the light fermion masses and mixings must come from higher-dimensional operators in the TeV scale EFT that derive from a further layer of new physics at a higher scale Λ ≈ 100 TeV.…”

Section: Jhep08(2021)101mentioning

confidence: 99%

“…q := (q 1 , q 2 ) ∼ (2, 1, 1). The third family quark fields q 3 , u 3 , and d 3 are singlets under U(2) 3 global . Here U(1) B 3 denotes third family baryon number.…”

Section: Jhep08(2021)101mentioning

confidence: 99%

“…When building models of new physics that extend the Standard Model (SM) gauge symmetry, it seems pragmatic to take our cue from the SM itself and require anomaly cancellation. For family non-universal U(1) extensions of the SM gauge group, the space of anomaly-free charge assignments for the SM fermions has recently been studied both numerically and analytically [1,2], and even parametrized explicitly in the special case where three SM singlet fermions are included [3]. Restricting the charges to lie on this anomaly-free subspace often leads to interesting correlations within the phenomenology.…”

Section: Introductionmentioning

confidence: 99%

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Anomalous Z′ bosons for anomalous B decays

Davighi

2021

J. High Energ. Phys.

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Motivated by the intriguing discrepancies in b → sℓℓ transitions, the fermion mass problem, and a desire to preserve the accidental symmetries of the Standard Model (SM), we extend the SM by an anomalous U(1)X gauge symmetry where X = Y3 + a(Lμ− Lτ)/6. The heavy Z′ boson associated with spontaneously breaking U(1)X at the TeV scale mediates the b → sℓℓ anomalies via $$ {\mathcal{O}}_9^{\mu}\sim \frac{1}{\Lambda^2}\left(\overline{s}{\gamma}_{\rho }{P}_Lb\right)\left(\overline{\mu}{\gamma}^{\rho}\mu \right) $$ O 9 μ ~ 1 Λ 2 s ¯ γ ρ P L b μ ¯ γ ρ μ . We show that this model, which features mixed gauge anomalies involving U(1)X and hypercharge, can be made anomaly-free for any a ∈ ℤ by integrating in a pair of charged fermions whose masses naturally reside somewhere between 1 and 30 TeV. The gauge symmetry permits only the third family Yukawas at the renormalisable level, and so the light quark masses and mixings are controlled by accidental U(2)3 flavour symmetries which we assume are minimally broken alongside U(1)X. The lepton sector is not governed by U(2) symmetries, but rather one expects a nearly diagonal charged lepton Yukawa with me,μ « mτ. The model does not explain the hierarchy me « mμ, but it does possess high quality lepton flavour symmetries that are robust to the heavy physics responsible for generating me,μ. We establish the viability of these models by checking agreement with the most important experimental constraints. We comment on how the model could also explain neutrino masses and the muon g − 2.

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Section: Jhep08(2021)101mentioning

confidence: 95%

Section: Jhep08(2021)101mentioning

confidence: 99%

“…q := (q 1 , q 2 ) ∼ (2, 1, 1). The third family quark fields q 3 , u 3 , and d 3 are singlets under U(2) 3 global . Here U(1) B 3 denotes third family baryon number.…”

Section: Jhep08(2021)101mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Anomalous Z′ bosons for anomalous B decays

Davighi

2021

J. High Energ. Phys.

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“…In order for the theory to be self-consistent, the U(1) charge assignment must be anomaly-free. The space of family-dependent anomaly-free U(1) extensions of the SM gauge symmetry has been well-studied recently [31][32][33][34], and is unhelpfully vast unless further criteria are imposed.…”

mentioning

confidence: 99%

Anomalies and accidental symmetries: charging the scalar leptoquark under Lμ − Lτ

Davighi

Kirk

Nardecchia

2020

J. High Energ. Phys.

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While the S3 scalar leptoquark presents a possible tree-level explanation of the b → sℓℓ flavour anomalies, it suffers from two conceptual problems which are often disregarded by model-builders. Firstly, the quantum numbers of the S3 allow for a renormalisable diquark operator that would trigger rapid proton decay unless its coupling were tuned away. Secondly, one expects the leptoquark to have generic couplings to leptons, which require tuning to avoid stringent experimental bounds on lepton flavour violation. By gauging a U(1) current that acts as Lμ− Lτ on the Standard Model (SM) fermions, and under which the leptoquark has charge −1, one can remedy both these problems. The additional U(1), which is spontaneously broken at some high scale, is associated with a massive Z′ gauge boson and a scalar SM singlet Φ, which play no direct role in mediating the anomalous B meson decays. By computing one- and two-loop mass corrections, we show that this pair of particles can be hidden away at much higher mass scales without destabilising either the Higgs or the leptoquark masses. The only low-energy relic of gauging Lμ− Lτ is thus the accidental global symmetry structure of the lagrangian. On the other hand, we find quite generally that an S3 leptoquark that mediates the b → sℓℓ anomalies cannot be much heavier than a few TeV without itself inducing large Higgs mass corrections.

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Ising Machines for Diophantine Problems in Physics

Abel

2022

Fortschritte der Physik

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Diophantine problems arise frequently in physics, in for example anomaly cancellation conditions, string consistency conditions and so forth. We present methods to solve such problems to high order on annealers that are based on the quadratic Ising Model. This is the intrinsic framework for both quantum annealing and for common forms of classical simulated annealing. We demonstrate the method on so-called Taxicab numbers (discovering some apparently new ones), and on the realistic problem of anomaly cancellation in U(1) extensions of the Standard Model.

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Anomaly Cancellation with an Extra Gauge Boson

Cited by 32 publications

References 10 publications

Anomalous Z′ bosons for anomalous B decays

Anomalous Z′ bosons for anomalous B decays

Anomalies and accidental symmetries: charging the scalar leptoquark under Lμ − Lτ

Ising Machines for Diophantine Problems in Physics

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