Clock--WEP Tests of String-Derived Dilaton and Modulus Sectors
Abstract
String compactifications and runaway-dilaton models can contain light scalar directions. Motion along these directions changes gauge couplings, the QCD scale, quark masses, and Yukawa parameters. A given string-derived sector then predicts low-energy slopes. Its gauge kinetic functions, matter-metric or Yukawa slopes, source charge, scalar trajectory, and scalar range determine a Damour--Donoghue weak-equivalence-principle (WEP) vector and a clock-drift vector. The fit assumes one long-range scalar or an aligned multi-field direction. With that assumption, WEP tests and secular clock drifts probe related projections of the same scalar-slope vector. The minimal two-charge Damour--Donoghue fit uses Ti--Pt MICROSCOPE, Be--Ti torsion-balance, and 85Rb--87Rb atom-interferometer data, then adds the Yb+ E3/E2 secular α-drift row. The WEP-only fit gives Dm̂=(−6.06±34.91)×10−12 and De=(8.80±46.46)×10−12, with correlation −0.99958. The clock input is α̇/α=1.0(1.1)×10−18 yr−1. It matches the WEP marginal reach when |ζ|=2.37×10−8 yr−1, with ζ=φ̇/αE. For the benchmark φ̇=ξH0 and αE=10−3α0, this gives ξ/α0≃0.34. A model becomes testable after it supplies r=Dm̂/De, the scalar amplitude, and ζ. The Damour--Piazza--Veneziano runaway-dilaton estimate lies near η∼10−12 for order-unity n=2 parameters, well above the MICROSCOPE-level WEP scale. In the representative-isotope two-charge model, a MICROSCOPE-level Be--Ti-like row would reduce the long WEP axis by a factor $27.8$; a repeated Ti--Pt-like row would barely change it. The calculation tests compactification-level predictions for string-derived dilaton or modulus sectors after the model supplies its low-energy data.
Versions
Related
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BibTeX
@misc{ali2026clockwep,
title = {{Clock--WEP Tests of String-Derived Dilaton and Modulus Sectors}},
author = {Ahmed Farag Ali},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.35947},
eprint = {2610.35947},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.35947},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Clock--WEP Tests of String-Derived Dilaton and Modulus Sectors
AU - Ahmed Farag Ali
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.35947
UR - https://arxiv.org/abs/2610.35947
AB - String compactifications and runaway-dilaton models can contain light scalar directions. Motion along these directions changes gauge couplings, the QCD scale, quark masses, and Yukawa parameters. A given string-derived sector then predicts low-energy slopes. Its gauge kinetic functions, matter-metric or Yukawa slopes, source charge, scalar trajectory, and scalar range determine a Damour--Donoghue weak-equivalence-principle (WEP) vector and a clock-drift vector. The fit assumes one long-range scalar or an aligned multi-field direction. With that assumption, WEP tests and secular clock drifts probe related projections of the same scalar-slope vector. The minimal two-charge Damour--Donoghue fit uses Ti--Pt MICROSCOPE, Be--Ti torsion-balance, and ^85Rb--^87Rb atom-interferometer data, then adds the Yb^+ E3/E2 secular α-drift row. The WEP-only fit gives D_m̂=(−6.06±34.91)×10^−12 and D_e=(8.80±46.46)×10^−12, with correlation −0.99958. The clock input is α̇/α=1.0(1.1)×10^−18 yr^−1. It matches the WEP marginal reach when |ζ|=2.37×10^−8 yr^−1, with ζ=φ̇/α_E. For the benchmark φ̇=ξH_0 and α_E=10^−3α_0, this gives ξ/α_0≃0.34. A model becomes testable after it supplies r=D_m̂/D_e, the scalar amplitude, and ζ. The Damour--Piazza--Veneziano runaway-dilaton estimate lies near η∼10^−12 for order-unity n=2 parameters, well above the MICROSCOPE-level WEP scale. In the representative-isotope two-charge model, a MICROSCOPE-level Be--Ti-like row would reduce the long WEP axis by a factor $27.8$; a repeated Ti--Pt-like row would barely change it. The calculation tests compactification-level predictions for string-derived dilaton or modulus sectors after the model supplies its low-energy data.
ER -