Most exact ever measurement of W boson mass reveals stress with the Normal Mannequin.
After 10 years of cautious evaluation and scrutiny, scientists of the CDF collaboration on the U.S. Division of Power’s Fermi Nationwide Accelerator Laboratory introduced on April 7, 2022, that they've achieved essentially the most exact measurement so far of the mass of the W boson, one in all nature’s force-carrying particles. Utilizing knowledge collected by the Collider Detector at Fermilab, or CDF, scientists have now decided the particle’s mass with a precision of 0.01% — twice as exact because the earlier greatest measurement. It corresponds to measuring the load of an 800-pound gorilla to 1.5 ounces.
The brand new precision measurement, printed within the journal Science, permits scientists to check the Normal Mannequin of particle physics, the theoretical framework that describes nature at its most basic degree. The end result: The brand new mass worth reveals stress with the worth scientists acquire utilizing experimental and theoretical inputs within the context of the Normal Mannequin.
The Collider Detector at Fermilab recorded high-energy particle collisions produced by the Tevatron collider from 1985 to 2011. About 400 scientists at 54 establishments in 23 nations are nonetheless engaged on the wealth of knowledge collected by the experiment. Credit score: Fermilab
“The variety of enhancements and additional checking that went into our result's huge,” stated Ashutosh V. Kotwal of Duke College, who led this evaluation and is among the 400 scientists within the CDF collaboration. “We took under consideration our improved understanding of our particle detector in addition to advances within the theoretical and experimental understanding of the W boson’s interactions with different particles. After we lastly unveiled the end result, we discovered that it differed from the Normal Mannequin prediction.”
If confirmed, this measurement suggests the potential want for enhancements to the Normal Mannequin calculation or extensions to the mannequin.
Scientists have now decided the mass of the W boson with a precision of 0.01%. That is twice as exact because the earlier greatest measurement and reveals stress with the Normal Mannequin.
The brand new worth is in settlement with many earlier W boson mass measurements, however there are additionally some disagreements. Future measurements will likely be wanted to shed extra mild on the end result.
“Whereas that is an intriguing end result, the measurement must be confirmed by one other experiment earlier than it may be interpreted totally,” stated Fermilab Deputy Director Joe Lykken.
The W boson is a messenger particle of the weak nuclear drive. It's answerable for the nuclear processes that make the solar shine and particles decay. Utilizing high-energy particle collisions produced by the Tevatron collider at Fermilab, the CDF collaboration collected enormous quantities of knowledge containing W bosons from 1985 to 2011.
The W boson is the messenger particle of the weak nuclear drive. It's answerable for the nuclear processes that make the solar shine and particles decay. CDF scientists are finding out the properties of the W boson utilizing knowledge they collected on the Tevatron Collider at Fermilab. Credit score: Fermi Nationwide Accelerator Laboratory
CDF physicist Chris Hays of the College of Oxford stated, “The CDF measurement was carried out over the course of a few years, with the measured worth hidden from the analyzers till the procedures had been totally scrutinized. After we uncovered the worth, it was a shock.”
The mass of a W boson is about 80 instances the mass of a proton, or roughly 80,000 MeV/c2. CDF researchers have labored on attaining more and more extra exact measurements of the W boson mass for greater than 20 years. The central worth and uncertainty of their newest mass measurement is 80,433 +/- 9 MeV/c2. This end result makes use of the whole dataset collected from the Tevatron collider at Fermilab. It's based mostly on the commentary of 4.2 million W boson candidates, about 4 instances the quantity used within the evaluation the collaboration printed in 2012.
The mass of a W boson is about 80 instances the mass of a proton, or roughly 80,000 MeV/c2. Scientists of the Collider Detector at Fermilab collaboration have achieved the world’s most exact measurement. The CDF worth has a precision of 0.01 % and is in settlement with many W boson mass measurements. It reveals stress with the worth anticipated based mostly on the Normal Mannequin of particle physics. The horizontal bars point out the uncertainty of the measurements achieved by varied experiments. The LHCb end result was printed after this paper was submitted and is 80354+- 32 MeV/c2. Credit score: CDF collaboration
“Many collider experiments have produced measurements of the W boson mass over the past 40 years,” stated CDF co-spokesperson Giorgio Chiarelli, Italian Nationwide Institute for Nuclear Physics (INFN-Pisa). “These are difficult, sophisticated measurements, they usually have achieved ever extra precision. It took us a few years to undergo all the small print and the wanted checks. It's our most strong measurement so far, and the discrepancy between the measured and anticipated values persists.”
The collaboration additionally in contrast their end result to the perfect worth anticipated for the W boson mass utilizing the Normal Mannequin, which is 80,357 ± 6 MeV/c2. This worth relies on complicated Normal Mannequin calculations that intricately hyperlink the mass of the W boson to the measurements of the plenty of two different particles: the highest quark, found on the Tevatron collider at Fermilab in 1995, and the Higgs boson, found on the Massive Hadron Collider at CERN in 2012.
CDF co-spokesperson David Toback, Texas A&M College, said the end result is a vital contribution to testing the accuracy of the Normal Mannequin. “It’s now as much as the theoretical physics group and different experiments to observe up on this and make clear this thriller,” he added. “If the distinction between the experimental and anticipated worth is because of some sort of new particle or subatomic interplay, which is among the potentialities, there’s an excellent probability it’s one thing that may very well be found in future experiments.”
Reference: “Excessive-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, Ok. 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, Ok. 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, Ok. 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. d’Ascenzo, M. Datta, P. de Barbaro, L. Demortier, M. Deninno, M. D’Errico, F. Devoto, A. Di Canto, B. Di Ruzza, J. R. Dittmann, S. Donati, M. D’Onofrio, M. Dorigo, A. Driutti, Ok. Ebina, R. Edgar, A. Elagin, R. Erbacher, S. Errede, B. Esham, S. Farrington, J. P. Fernández Ramos, R. Area, 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, Ok. 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, Ok. Goulianos, E. Gramellini, C. Grosso-Pilcher, J. Guimaraes da Costa, S. R. Hahn, J. Y. Han, F. Happacher, Ok. Hara, M. Hare, R. F. Harr, T. Harrington-Taber, Ok. 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, Ok. Yamamoto, D. Yamato, T. Yang, U. Ok. Yang, Y. C. Yang, W.-M. Yao, G. P. Yeh, Ok. Yi, J. Yoh, Ok. 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 collaboration contains 400 scientists at 54 establishments in 23 nations.
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