ترغب بنشر مسار تعليمي؟ اضغط هنا

Testing for Lorentz Violation: Constraints on Standard-Model Extension Parameters via Lunar Laser Ranging

154   0   0.0 ( 0 )
 نشر من قبل James Battat
 تاريخ النشر 2007
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

We present constraints on violations of Lorentz Invariance based on Lunar Laser Ranging (LLR) data. LLR measures the Earth-Moon separation by timing the round-trip travel of light between the two bodies, and is currently accurate to a few centimeters (parts in $10^{11}$ of the total distance). By analyzing archival LLR data under the Standard-Model Extension (SME) framework, we derived six observational constraints on dimensionless SME parameters that describe potential Lorentz-violation. We found no evidence for Lorentz violation at the $10^{-6}$ to $10^{-11}$ level in these parameters.



قيم البحث

اقرأ أيضاً

We present new constraints on Lorentz symmetry (LS) violations with lunar laser ranging (LLR). Those constraints are derived in the standard-model extension (SME) framework aiming at parameterizing any LS deviations in all sectors of physics. We rest rict ourself to two sectors namely the pure gravitational sector of the minimal SME and the gravity-matter coupling. We describe the adopted method and compare our results to previous analysis based on theoretical grounds. This work constitutes the first direct experimental determination of the SME coefficients using LLR measurements.
86 - Shinji Tsujikawa 2019
In dark energy models where a scalar field $phi$ is coupled to the Ricci scalar $R$ of the form $e^{-2Q (phi-phi_0)/M_{rm pl}}R$, where $Q$ is a coupling constant, $phi_0$ is todays value of $phi$, and $M_{rm pl}$ is the reduced Planck mass, we study how the recent Lunar Laser Ranging (LLR) experiment places constraints on the nonminimal coupling from the time variation of gravitational coupling. Besides a potential of the light scalar responsible for cosmic acceleration, we take a cubic Galileon term into account to suppress fifth forces in over-density regions of the Universe. Even if the scalar-matter interaction is screened by the Vainshtein mechanism, the time variation of gravitational coupling induced by the cosmological background field $phi$ survives in the solar system. For a small Galileon coupling constant $beta_3$, there exists a kinetically driven $phi$-matter-dominated-epoch ($phi$MDE) prior to cosmic acceleration. In this case, we obtain the stringent upper limit $Q le 3.4 times 10^{-3}$ from the LLR constraint. For a large $beta_3$ without the $phi$MDE, the coupling $Q$ is not particularly bounded from above, but the cosmological Vainshtein screening strongly suppresses the time variation of $phi$ such that the dark energy equation of state $w_{rm DE}$ reaches the value close to $-1$ at high redshifts. We study the modified gravitational wave propagation induced by the nonminimal coupling to gravity and show that, under the LLR bound, the difference between the gravitational wave and luminosity distances does not exceed the order $10^{-5}$ over the redshift range $0<z<100$. In dark energy models where the Vainshtein mechanism is at work through scalar derivative self-interactions, it is difficult to probe the signature of nonminimal couplings from the observations of standard sirens.
We study the impact of the limit on $|dot{G}|/G$ from Lunar Laser Ranging on nonlocal gravity, i.e. on models of the quantum effective action of gravity that include nonlocal terms relevant in the infrared, such as the RR and RT models proposed by ou r group, and the Deser-Woodard (DW) model. We elaborate on the analysis of Barreira et al. [1] and we confirm their findings that (under plausible assumptions such as the absence of strong backreaction from non-linear structures), the RR model is ruled out. We also show that the mechanism of perfect screening for free suggested for the DW model actually does not work and the DW model is also ruled out. In contrast, the RT model passes all phenomenological consistency tests and is still a viable candidate.
We present the first constraints on pure-gravity sector Standard-Model Extension (SME) parameters using Lunar Laser Ranging (LLR). LLR measures the round trip travel time of light between the Earth and the Moon. With 34+ years of LLR data, we have co nstrained six independent linear combinations of SME parameters at the level of $10^{-6}$ to $10^{-11}$. There is no evidence for Lorentz violation in the LLR dataset.
89 - A. Bourgoin 2020
The possibility for Lorentz/CPT-breaking, which is motivated by unification theories, can be systematically tested within the standard-model extension framework. In the pure gravity sector, the mass dimension 5 operators produce new Lorentz and CPT-b reaking terms in the 2-body equations of motion that depend on the relative velocity of the bodies. In this Letter, we report new constraints on 15 independent SME coefficients for Lorentz/CPT-violations with mass dimension 5 using lunar laser ranging. We perform a global analysis of lunar ranging data within the SME framework using more than 26,000 normal points between 1969 and 2018. We also perform a jackknife analysis in order to provide realistic estimates of the systematic uncertainties. No deviation from Lorentz/CPT symmetries is reported. In addition, when fitting simultaneously for the 15 canonical SME coefficients for Lorentz/CPT-violations, we improve up to three orders of magnitude previous post-fit constraints from radio pulsars.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا