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The effect of the Gaussian profile of the new Higgs doublet on the radiative lepton flavor violating decay

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E. O. Iltan

High Energy Physics - Phenomenology · Submitted 19 Feb 2006 · 38 references

Pith's reading: Branching ratios for mu -> e gamma, tau -> e gamma and tau -> mu gamma are computed in a 2HDM with one extra dimension and a Gaussian-localized second Higgs doublet, yielding roughly 10^-12, 10^-16 and 10^-12 for hand-chosen Yukawa couplings and model parameters.

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arXiv IDhep-ph/0602170 (version 1)
Pith IDSH6O66N5, Pith's permanent record of this paper and its review
CitationE. O. Iltan. "The effect of the Gaussian profile of the new Higgs doublet on the radiative lepton flavor violating decay." arXiv:hep-ph/0602170 (2006). https://pith.science/paper/SH6O66N5
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Claim paper
The paper

The paper claims

Branching ratios for mu -> e gamma, tau -> e gamma and tau -> mu gamma are computed in a 2HDM with one extra dimension and a Gaussian-localized second Higgs doublet, yielding roughly 10^-12, 10^-16 and 10^-12 for hand-chosen Yukawa couplings and model parameters.

The reading

Lepton flavor violation means a muon or tau can change into a different lepton while emitting a photon. In the Standard Model this is virtually impossible because neutrino masses are tiny. Many extensions of particle physics predict larger rates, so experiments like MEG look for these rare decays.

This paper works in a model with two Higgs doublets and one extra spatial dimension. In such models, new neutral Higgs bosons can circulate in loops and generate mu -> e gamma and tau -> l gamma transitions. The new ingredient is that the second Higgs doublet is assumed to be localized in the extra dimension with a Gaussian-shaped wave function, rather than spread uniformly. The width of that Gaussian and the point where it is centered are treated as free parameters.

The author computes the branching ratios for three decays: mu -> e gamma, tau -> e gamma and tau -> mu gamma. With Yukawa couplings of order 50 to 100 GeV, a compactification scale of 200 to 1000 GeV, and a narrow Gaussian width, the rates come out near 10^-12, 10^-16 and 10^-12 respectively. Moving the Gaussian center away from the origin suppresses the rates by up to about 45 percent. Wider Gaussians increase the rates by roughly four orders of magnitude over the scanned width range.

The numbers are not predictions in the usual sense: they are outputs of freely chosen couplings and model parameters. The paper also scans compactification scales that its own cited experimental bounds disfavor. No code or data tables are provided, and the decay amplitude is presented without derivation.

Extended reading notes

Core claim

The branching ratios of the LFV decays mu -> e gamma, tau -> e gamma and tau -> mu gamma are at the order of 10^-12, 10^-16 and 10^-12 in the considered range of the free parameters, and they are strongly sensitive to the Gaussian width of the localized neutral Higgs scalars, increasing by about four orders of magnitude for 0.005 <= rho <= 0.05.

Load-bearing premise

The calculation assumes the new Higgs doublet zero mode is localized with a Gaussian profile S(x,y)=A exp(-beta y^2) by an unknown mechanism, while all lepton and SM Higgs zero modes remain uniform (Eq. (5), footnote 1), and the KK excitations of the new Higgs scalars are neglected because their masses are assumed heavy. If the localization profile is not Gaussian, or the Higgs KK modes are not negligible, the overlap factors c_n in Eqs. (10) and (15) and therefore all three branching ratios change.

Original abstract

We study the branching ratios of the lepton flavor violating processes \mu -> e\gamma, \tau -> e\gamma and \tau -> \mu\gamma by considering that the new Higgs scalars localize with Gaussian profile in the extra dimension. We see that the BRs of the LFV decays \mu -> e \gamma, \tau -> e \gamma and \tau -> \mu\gamma are at the order of the magnitude of 10^{-12}, 10^{-16} and 10^{-12} in the considered range of the free parameters. These numerical values are slightly suppressed in the case that the localization points of new Higgs scalars are different than origin.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 3,125 input tokens, $0.0001 reported.

What the abstract itself states, as probabilities: claims first 0.02 · states limitation 0.45 · human participants 0.01 · controlled comparison 0.32 · randomized assignment 0.01 · states quantitative result 0.98 · compares with prior results 0.13 · mentions code or data availability 0.01.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

We study the branching ratios of the lepton flavor violating processes \mu -> e\gamma, \tau -> e\gamma and \tau -> \mu\gamma by considering that the new Higgs scalars localize with Gaussian profile in the extra dimension. We see that the BRs of the LFV decays \mu -> e \gamma, \tau -> e \gamma and \tau -> \mu\gamma are at the order of the magnitude of 10^{-12}, 10^{-16} and 10^{-12} in the considered range of the free parameters. These numerical values are slightly suppressed in the case that the localization points of new Higgs scalars are different than origin.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 We study the branching ratios of the lepton flavor violating processes \mu -> e\gamma, \tau -> e\gamma and \tau -> \mu\gamma by considering that the new Higgs scalars localize with Gaussian profile in the extra dimension. contribution 0.97 0.90 0.07 asserted 0.89
s1 We see that the BRs of the LFV decays \mu -> e \gamma, \tau -> e \gamma and \tau -> \mu\gamma are at the order of the magnitude of 10^{-12}, 10^{-16} and 10^{-12} in the considered range of the free parameters. result 1.00 0.93 0.66 asserted 1.00
s2 These numerical values are slightly suppressed in the case that the localization points of new Higgs scalars are different than origin. result 0.95 0.88 0.13 asserted 0.99

What kind of paper the classifier reports this is: theoretical result 0.74 · evidence from simulation or computation 0.98.

What was examined, and what was not

sources read
  • arXiv listing abstract v1
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

Figures
Figure 1. One loop diagrams contribute to l1 → l2γ decay due to the zero mode neutral Higgs bosons h 0 and A0 in the 2HDM, for a single extra dimension. Here l n i represents the internal KK mode charged lepton and n=0,1, ... 12
Figure 2. The BR(µ → eγ) with respect to ρ. Here the lower-upper solid (dashed), line represents the BR for a single extra dimension without-with lepton KK modes, the real couplings ¯ξ E N,τµ = 50 GeV , ¯ξ E N,τe = 0.1 GeV ( ¯ξ E N,τe = 0.5 GeV ) and R = 0.005 GeV −1 . ρ 1018 × BR 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05 1000 100 10 1 0.1 0.01 0.001 0.0001
Figure 3. The BR(τ → eγ) with respect to ρ. Here the lower-upper solid (dashed), line repre￾sents the BR for a single extra dimension without-with lepton KK modes, for R = 0.005 GeV −1 , the real couplings ¯ξ E N,ττ = 100 GeV , ¯ξ E N,τe = 0.1 GeV ( ¯ξ E N,τe = 0.5 GeV ). 13
Figure 4. The BR(τ → µγ) with respect to ρ. Here the lower-upper solid (dashed), line repre￾sents the BR for a single extra dimension without-with lepton KK modes, for R = 0.005 GeV −1 , the real couplings ¯ξ E N,ττ = 100 GeV , ¯ξ E N,τµ = 50 GeV ( ¯ξ E N,τµ = 80 GeV ). 1/R (GeV ) 1014 × BR 100 200 300 400 500 600 700 800 900 1000 10 1 0.1 0.01
Figure 5. The BR(µ → eγ) with respect to the compactification scale 1/R. Here the lower￾upper solid (dashed), line represents the BR for a single extra dimension without-with lepton KK modes, the real couplings ¯ξ E N,τµ = 50 GeV , ¯ξ E N,τe = 0.1 GeV ( ¯ξ E N,τe = 0.5 GeV ) and ρ = 0.01. 14
Figure 6. BR(τ → eγ) with respect to the compactification scale 1/R. Here the lower-upper solid (dashed), line represents the BR for a single extra dimension without-with lepton KK modes, the real couplings ¯ξ E N,ττ = 100 GeV , ¯ξ E N,τe = 0.1 GeV ( ¯ξ E N,τe = 0.5 GeV ) and ρ = 0.01. 1/R (GeV ) 1012 × BR 100 200 300 400 500 600 700 800 900 1000 0.1 0.01 0.001
Figure 7. BR(τ → µγ) with respect to the compactification scale 1/R. Here the lower-upper solid (dashed), line represents the BR for a single extra dimension without-with lepton KK modes, the real couplings ¯ξ E N,ττ = 100 GeV , ¯ξ E N,τµ = 50 GeV ( ¯ξ E N,τµ = 80 GeV ) and ρ = 0.01. 15
Figure 8. The BR(µ → eγ) with respect to α. Here the lower-upper solid (dashed), line represents the BR for a single extra dimension with lepton KK modes, for yH = 0 − yH = α σ, the real couplings ¯ξ E N,τµ = 50 GeV , ¯ξ E N,τe = 0.1 GeV ( ¯ξ E N,τe = 0.5 GeV ) and R = 0.005 GeV −1 α 1018 × BR 1 2 3 4 5 6 7 8 9 10 1000 100 10
Figure 9. The BR(τ → eγ) with respect to α. Here the lower-upper solid (dashed), line represents the BR for a single extra dimension with lepton KK modes, for yH = 0 − yH = α σ, the real couplings ¯ξ E N,ττ = 100 GeV , ¯ξ E N,τe = 0.1 GeV ( ¯ξ E N,τe = 0.5 GeV ) and R = 0.005 GeV −1 . 16
Figure 10. The BR(τ → µγ) with respect to α. Here the lower-upper solid (dashed), line represents the BR for a single extra dimension with lepton KK modes, for yH = 0 − yH = α σ, the real couplings ¯ξ E N,τµ = 50 GeV ( ¯ξ E N,τµ = 80 GeV ) and R = 0.005 GeV −1 . 17

Figures reproduced from arXiv:hep-ph/0602170 by the authors.

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