May 6, 2024

Particle Physics Shock: Most Precise Ever Measurement of W Boson Mass Differs From Standard Model Prediction

Many accurate ever measurement of W boson mass to be in tension with the Standard Model.
After 10 years of cautious analysis and examination, researchers of the CDF cooperation at the U.S. Department of Energys Fermi National Accelerator Laboratory revealed on April 7, 2022, that they have attained the most exact measurement to date of the mass of the W boson, among natures force-carrying particles. Utilizing data gathered by the Collider Detector at Fermilab, or CDF, scientists have actually now identified the particles mass with a precision of 0.01%– twice as exact as the previous finest measurement. It corresponds to measuring the weight of an 800-pound gorilla to 1.5 ounces.
The new accuracy measurement, released in the journal Science, enables scientists to evaluate the Standard Model of particle physics, the theoretical structure that describes nature at its most fundamental level. The result: The new mass value shows tension with the worth scientists get utilizing experimental and theoretical inputs in the context of the Standard Model.

After 10 years of careful analysis and analysis, scientists of the CDF collaboration at the U.S. Department of Energys Fermi National Accelerator Laboratory revealed on April 7, 2022, that they have actually achieved the most exact measurement to date of the mass of the W boson, one of natures force-carrying particles. Utilizing information collected by the Collider Detector at Fermilab, or CDF, researchers have now determined the particles mass with a precision of 0.01%– two times as precise as the previous finest measurement. CDF scientists have actually worked on accomplishing significantly more exact measurements of the W boson mass for more than 20 years. The CDF worth has an accuracy of 0.01 percent and is in agreement with numerous W boson mass measurements.” Many collider experiments have actually produced measurements of the W boson mass over the last 40 years,” said CDF co-spokesperson Giorgio Chiarelli, Italian National Institute for Nuclear Physics (INFN-Pisa).

The Collider Detector at Fermilab recorded high-energy particle crashes produced by the Tevatron collider from 1985 to 2011. About 400 researchers at 54 organizations in 23 countries are still dealing with the wealth of data gathered by the experiment. Credit: Fermilab
” The number of enhancements and additional checking that entered into our outcome is huge,” said Ashutosh V. Kotwal of Duke University, who led this analysis and is among the 400 researchers in the CDF collaboration. “We considered our enhanced understanding of our particle detector along with advances in the speculative and theoretical understanding of the W bosons interactions with other particles. When we lastly revealed the result, we found that it differed from the Standard Model prediction.”
If verified, this measurement recommends the prospective need for improvements to the Standard Model computation or extensions to the design.
Scientists have actually now identified the mass of the W boson with an accuracy of 0.01%. This is two times as accurate as the previous best measurement and reveals tension with the Standard Model.
The brand-new value is in contract with lots of previous W boson mass measurements, however there are also some differences. Future measurements will be needed to shed more light on the result.
” While this is an interesting outcome, the measurement needs to be validated by another experiment prior to it can be translated totally,” stated Fermilab Deputy Director Joe Lykken.
The W boson is a messenger particle of the weak nuclear force. It is accountable for the nuclear processes that make the sun shine and particles decay. Using high-energy particle crashes produced by the Tevatron collider at Fermilab, the CDF collaboration gathered big quantities of information consisting of W bosons from 1985 to 2011.
The W boson is the messenger particle of the weak nuclear force. It is accountable for the nuclear procedures that make the sun shine and particles decay. CDF researchers are studying the properties of the W boson using information they gathered at the Tevatron Collider at Fermilab. Credit: Fermi National Accelerator Laboratory
CDF physicist Chris Hays of the University of Oxford said, “The CDF measurement was performed throughout several years, with the determined worth concealed from the analyzers until the treatments were fully scrutinized. When we revealed the worth, it was a surprise.”
CDF researchers have worked on accomplishing increasingly more accurate measurements of the W boson mass for more than 20 years. The main worth and uncertainty of their latest mass measurement is 80,433 +/- 9 MeV/c2.
The mass of a W boson is about 80 times the mass of a proton, or roughly 80,000 MeV/c2. Scientists of the Collider Detector at Fermilab cooperation have actually achieved the worlds most accurate measurement. The CDF value has an accuracy of 0.01 percent and is in agreement with lots of W boson mass measurements. It shows stress with the worth expected based upon the Standard Model of particle physics. The horizontal bars suggest the unpredictability of the measurements attained by various experiments. The LHCb result was released after this paper was submitted and is 80354+- 32 MeV/c2. Credit: CDF collaboration
” Many collider experiments have produced measurements of the W boson mass over the last 40 years,” stated CDF co-spokesperson Giorgio Chiarelli, Italian National Institute for Nuclear Physics (INFN-Pisa). It is our most robust measurement to date, and the discrepancy in between the measured and anticipated worths continues.”
The partnership likewise compared their result to the finest value expected for the W boson mass using the Standard Model, which is 80,357 ± 6 MeV/c2. This worth is based on intricate Standard Model calculations that elaborately link the mass of the W boson to the measurements of the masses of two other particles: the top quark, found at the Tevatron collider at Fermilab in 1995, and the Higgs boson, found at the Large Hadron Collider at CERN in 2012.
CDF co-spokesperson David Toback, Texas A&M University, specified the result is a crucial contribution to testing the accuracy of the Standard Model. “Its now up to the theoretical physics neighborhood and other experiments to follow up on this and clarified this mystery,” he included. “If the difference between the predicted and speculative value is because of some kind of new particle or subatomic interaction, which is among the possibilities, theres a great chance its something that could be found in future experiments.”
Referral: “High-precision measurement of the W boson mass with the CDF II detector” by CDF Collaboration, T. Aaltonen, S. Amerio, D. Amidei, A. Anastassov, A. Annovi, J. Antos, G. Apollinari, J. A. Appel, T. Arisawa, A. Artikov, J. Asaadi, W. Ashmanskas, B. Auerbach, A. Aurisano, F. Azfar, W. Badgett, T. Bae, A. Barbaro-Galtieri, V. E. Barnes, B. A. Barnett, P. Barria, P. Bartos, M. Bauce, F. Bedeschi, S. Behari, G. Bellettini, J. Bellinger, D. Benjamin, A. Beretvas, A. Bhatti, K. R. Bland, B. Blumenfeld, A. Bocci, A. Bodek, D. Bortoletto, J. Boudreau, A. Boveia, L. Brigliadori, C. Bromberg, E. Brucken, J. Budagov, H. S. Budd, K. Burkett, G. Busetto, P. Bussey, P. Butti, A. Buzatu, A. Calamba, S. Camarda, M. Campanelli, B. Carls, D. Carlsmith, R. Carosi, S. Carrillo, B. Casal, M. Casarsa, A. Castro, P. Catastini, D. Cauz, V. Cavaliere, A. Cerri, L. Cerrito, Y. C. Chen, M. Chertok, G. Chiarelli, G. Chlachidze, K. Cho, D. Chokheli, A. Clark, C. Clarke, M. E. Convery, J. Conway, M. Corbo, M. Cordelli, C. A. Cox, D. J. Cox, M. Cremonesi, D. Cruz, J. Cuevas, R. Culbertson, N. dAscenzo, M. Datta, P. de Barbaro, L. Demortier, M. Deninno, M. DErrico, F. Devoto, A. Di Canto, B. Di Ruzza, J. R. Dittmann, S. Donati, M. DOnofrio, M. Dorigo, A. Driutti, K. Ebina, R. Edgar, A. Elagin, R. Erbacher, S. Errede, B. Esham, S. Farrington, J. P. Fernández Ramos, R. Field, G. Flanagan, R. Forrest, M. Franklin, J. C. Freeman, H. Frisch, Y. Funakoshi, C. Galloni, A. F. Garfinkel, P. Garosi, H. Gerberich, E. Gerchtein, S. Giagu, V. Giakoumopoulou, K. Gibson, C. M. Ginsburg, N. Giokaris, P. Giromini, V. Glagolev, D. Glenzinski, M. Gold, D. Goldin, A. Golossanov, G. Gomez, G. Gomez-Ceballos, M. Goncharov, O. González López, I. Gorelov, A. T. Goshaw, K. Goulianos, E. Gramellini, C. Grosso-Pilcher, J. Guimaraes da Costa, S. R. Hahn, J. Y. Han, F. Happacher, K. Hara, M. Hare, R. F. Harr, T. Harrington-Taber, K. Hatakeyama, C. Hays, J. Heinrich, M. Herndon, A. Hocker, Z. Hong, W. Hopkins, S. Hou, R. E. Hughes, U. Husemann, M. Hussein, J. Huston, G. Introzzi, M. Iori, A. Ivanov, E. James, D. Jang, B. Jayatilaka, E. J. Jeon, S. Jindariani, M. Jones … P. Wagner, R. Wallny, S. M. Wang, D. Waters, W. C. Wester, D. Whiteson, A. B. Wicklund, S. Wilbur, H. H. Williams, J. S. Wilson, P. Wilson, B. L. Winer, P. Wittich, S. Wolbers, H. Wolfmeister, T. Wright, X. Wu, Z. Wu, K. Yamamoto, D. Yamato, T. Yang, U. K. Yang, Y. C. Yang, W.-M. Yao, G. P. Yeh, K. Yi, J. Yoh, K. Yorita, T. Yoshida, G. B. Yu, I. Yu, A. M. Zanetti, Y. Zeng, C. Zhou and S. Zucchelli, 7 April 2022, Science.DOI: 10.1126/ science.abk1781.
The CDF partnership makes up 400 researchers at 54 organizations in 23 countries.