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Power to the LHC data: an ASYmptotically MOdel-independent measurement of the W boson mass

Project description

A clean slate and a huge data set could help constrain the W boson’s mass

According to the Standard Model of particle physics, our entire Universe consists of 17 fundamental particles. These include the building blocks of matter, six quarks and six leptons, and five force carrying particles, including the W boson. The W boson was discovered about four decades ago, and scientists are still trying to determine its mass accurately. There is a discrepancy between its expected value based on the Standard Model and its experimentally determined one. The EU funded ASYMOW project will try a novel approach, throwing prior knowledge to the wind and instead relying on the large amount of available data from the most advanced experiments.

Objective

Despite its success in describing the sub-nuclear realm, the Standard Model of particle and field interactions cannot account for a number of experimental facts that constitute evidence of new and unknown physics. Sitting at both the energy and intensity frontier, the LHC grants the highest chances for solving the current puzzle. By exploiting the data collected by the CMS experiment at the LHC, ASYMOW aims at attaining an unprecedented experimental accuracy on a fundamental parameter of Nature: the mass of the W boson. As of today, there is a tension between the Standard Model expectation and the measured value of the W boson mass. A new measurement with a 10 MeV uncertainty, i.e. twice as small as the single best measurement, is a breakthrough: it could either rule out the tension or build a convincing case that this anomaly is real, thus implying the existence of new physics. The collider physics community has been pursuing this goal for decades. The quest now seems to have hit the wall of systematic uncertainty. This project proposes a new approach towards the W boson mass measurement, which will circumvent the systematic uncertainties that are currently limiting the precision. The novelty of the proposed method lies in its agnosticism with respect to the microscopic picture of W boson production in hadron collisions. The loss of prior knowledge inherent to this new approach will be asymptotically compensated by the large amount of data available for the measurement, as will be collected at the LHC. ASYMOW will be conducted by a small group of scientists and comes with great experimental and theoretical challenges. The main expected result is the measurement of the W boson mass with a precision better than the state-of-the-art. This may open new scenarios in particle physics.

Host institution

UNIVERSITA DI PISA
Net EU contribution
€ 936 250,00
Address
LUNGARNO PACINOTTI 43/44
56126 Pisa
Italy

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Region
Centro (IT) Toscana Pisa
Activity type
Higher or Secondary Education Establishments
Links
Total cost
€ 936 250,00

Beneficiaries (3)