Search for Physics Beyond the Standard Model through ultra-rare Kaon decays with the NA62 Experiment at CERN

通过 CERN 的 NA62 实验通过超罕见的 Kaon 衰变寻找超越标准模型的物理

• 批准号: ST/M005798/1
• 负责人: Giuseppe Ruggiero
• 金额: $ 60.88万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FM005798%2F1
• 关键词: Search; Physics; Beyond; Standard; Model

The Standard Model of particle physics (SM) fully describes high energy interactions in normal matter, as witness the discovery of the Higgs-like boson at LHC at CERN, without explaining dark matter or dark energy. Two approaches pursued in particle physics to search beyond the SM are the direct search for new particles at high energy, and the study of rare decays precisely predicted by the SM. The NA62 experiment at CERN is designed to pursue this second approach by precisely measuring the decay of the charged kaon into a pion and two neutrinos that is predicted very precisely by the SM to occur only once for every ten billion times that a kaon decays into everything else possible. The hope is to find something different from the prediction to help us to explain why the SM works so well and to understand how to improve it.The entire system of detectors for NA62 takes up 270 metres and is located at CERN in an underground cavern. Kaon mesons do not exist in ordinary matter and about fifty million of them are produced per second, together with another billion pions and muons, by more than one thousand billion protons per second extracted from the SPS CERN accelerator and interacting with a beryllium target. The NA62 detectors are designed to recognize the kaons and to measure all the different types of particles that can be produced in their decay. The key ingredients are: i) kaon identification by measuring the Cherenkov radiation specific to their mass and speed, ii) precise reconstruction of the decay of the kaon, iii) the separation between pions, muons and electrons by measuring their masses and energies, and iv) the identification of photons with an accuracy of better than one part in a hundred thousand. It is vital that no particles escape detection and to this end an instrumented volume of liquid krypton measures the energy and position of the high-energy electrons and photons travelling forwards, while a system of 12 lead-glass detectors around the beamline detects all remaining photons. In order to perturb as little as possible the momentum and angles of the charged particles, lightweight straw-tubes have been built into two pairs of chambers, separated by a bending magnet producing a large magnetic field, to measure their position and momentum. This enables us to use the conservation of energy and momentum to reject much of the background to the wanted decay. A 17-metre-long Cherenkov detector filled with gaseous Neon has been installed to improve the distinction between charged pions and muons, provided principally by a calorimeter built from iron plates separated by scintillators that measure the energy released when the particles come to rest. The experiment is designed to keep all of the rare decays we wish to study and to sample all other kaon decays in an unbiased way with very low probability. The key point in reconstructing the final state particles is not just that they are consistent with the very rare decay we are seeking, but that they are not consistent with any other type of decay. To do this in a reliable way we must measure all backgrounds from data rather than relying on simulation. The experiment is scheduled to run up to 2018. The 2014 and 2015 data should allow us to observe a few of the very rare kaon decays into a pion and two neutrinos at the level of the Standard Model sensitivity, while the precision measurement of the decay probability will be achievable only at the end of the data taking. This measurement, together with the results from the many future direct and indirect searches produced concurrently at LHC, will help to distinguish the mechanisms beyond the Standard Model that may produce a coherent picture of the observed universe.

粒子物理标准模型（SM）完全描述了正常物质中的高能相互作用，就像在欧洲核子研究中心（CERN）的大型强子对撞机（LHC）上发现的希格斯类玻色子一样，但没有解释暗物质或暗能量。在粒子物理学中寻求超越SM的两种方法是直接寻找高能量的新粒子，以及研究SM精确预测的罕见衰变。欧洲核子研究中心（CERN）的NA62实验旨在通过精确测量带电的介子衰变为介子和两个中微子的过程来实现第二种方法，这种衰变被SM非常精确地预测为介子衰变为其他一切可能的物质的100亿次中只发生一次。我们希望找到一些不同于预测的东西来帮助我们解释为什么SM如此有效，并了解如何改进它。整个NA62探测器系统占地270米，位于欧洲核子研究中心的一个地下洞穴中。普通物质中不存在介子，每秒产生大约五千万个介子，加上另外十亿个介子和介子，从SPS CERN加速器中每秒提取超过一万亿个质子，并与铍靶相互作用。NA62探测器的设计目的是识别介子，并测量介子衰变过程中可能产生的所有不同类型的粒子。关键成分是：1)通过测量与其质量和速度相关的切伦科夫辐射来识别介子，2)精确重建介子的衰变，3)通过测量介子、介子和电子的质量和能量来分离介子，4)以优于十万分之一的精度识别光子。至关重要的是，没有任何粒子能逃脱检测，为此，一个仪器体积的液态氪测量向前移动的高能电子和光子的能量和位置，而束线周围的12个铅玻璃探测器系统检测所有剩余的光子。为了尽可能少地干扰带电粒子的动量和角度，轻质吸管管被置于两对腔室中，由产生大磁场的弯曲磁铁隔开，以测量它们的位置和动量。这使我们能够利用能量和动量守恒来排除所需衰变的大部分背景。为了更好地区分带电的介子和介子，已经安装了一个17米长的切伦科夫探测器，里面充满了气态氖。这个探测器主要是由一个量热计提供的，这个量热计是由由闪烁体隔开的铁板制成的，闪烁体测量粒子静止时释放的能量。该实验旨在保留我们希望研究的所有罕见衰变，并以非常低的概率以无偏的方式对所有其他k介子衰变进行采样。重建最终态粒子的关键点不仅在于它们与我们正在寻找的非常罕见的衰变相一致，而且在于它们与任何其他类型的衰变都不一致。为了以可靠的方式做到这一点，我们必须从数据中测量所有背景，而不是依靠模拟。该实验计划持续到2018年。2014年和2015年的数据应该允许我们在标准模型的灵敏度水平上观察到一些非常罕见的介子衰变为一个介子和两个中微子，而只有在数据采集结束时才能实现对衰变概率的精确测量。这一测量结果，加上未来在大型强子对撞机上同时进行的许多直接和间接搜索的结果，将有助于区分标准模型之外的机制，这些机制可能会产生一幅观测到的宇宙的连贯图景。

项目成果

Search for p° decays to invisible particles

寻找 p° 衰变为不可见粒子

• DOI: 10.5445/ir/1000130043
• 发表时间: 2021
• 作者: Cortina Gil E

Search for heavy neutral lepton production in K+ decays to positrons

• DOI: 10.1016/j.physletb.2020.135599
• 发表时间: 2020-05
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: E. Gil;A. Kleimenova;E. Minucci;S. Padolski;P. Petrov;A. Shaikhiev;R. Volpe;T. Numao;Y. Petrov;B. Velghe;D. Bryman;Jie Fu;T. Husek;J. Jerhot;K. Kampf;M. Zamkovsky;R. Aliberti;G. Khoriauli;J. Kunze;D. Lomidze;L. Peruzzo;M. Vormstein;R. Wanke;P. Dalpiaz;M. Fiorini;I. Neri;A. Norton;F. Petrucci;H. Wahl;A. C. Ramusino;A. Gianoli;E. Iacopini;G. Latino;M. Lenti;A. Parenti;A. Bizzeti;F. Bucci;A. Antonelli;G. Georgiev;V. Kozhuharov;G. Lanfranchi;S. Martellotti;M. Moulson;T. Spadaro;F. Ambrosino;T. Capussela;M. Corvino;D. Filippo;P. Massarotti;M. Mirra;M. Napolitano;G. Saracino;G. Anzivino;F. Brizioli;E. Imbergamo;R. Lollini;R. Piandani;C. Santoni;M. Barbanera;P. Cenci;B. Checcucci;P. Lubrano;M. Lupi;M. Pepe;M. Piccini;F. Costantini;L. Lella;N. Doble;M. Giorgi;S. Giudici;G. Lamanna;E. Lari;E. Pedreschi;M. Sozzi;C. Cerri;R. Fantechi;L. Pontisso;F. Spinella;I. Mannelli;G. D'Agostini;M. Raggi;A. Biagioni;Emilio Leonardi;A. Lonardo;P. Valente;P. Vicini;R. Ammendola;V. Bonaiuto;A. Fucci;A. Salamon;F. Sargeni;R. Arcidiacono;B. Bloch-Devaux;M. Boretto;E. Menichetti;E. Migliore;D. Soldi;C. Biino;A. Filippi;F. Marchetto;J. Engelfried;N. Estrada-Tristan;A. Bragadireanu;S. Ghinescu;O. Hutanu;A. Baeva;D. Baigarashev;D. Emelyanov;T. Enik;V. Falaleev;V. Kekelidze;A. Korotkova;L. Litov;D. Madigozhin;M. Misheva;N. Molokanova;S. Movchan;I. Polenkevich;Y. Potrebenikov;S. Shkarovskiy;A. Zinchenko;S. Fedotov;E. Gushchin;A. Khotyantsev;Y. Kudenko;V. Kurochka;M. Medvedeva;A. Mefodev;S. Kholodenko;V. Kurshetsov;V. Obraztsov;A. Ostankov;V. Semenov;V. Sugonyaev;O. Yushchenko;L. Bician;T. Blazek;V. Cerný;Z. Kučerová;J. Bernhard;A. Ceccucci;H. Danielsson;N. Simone;F. Duval;B. Döbrich;L. Federici;E. Gamberini;L. Gatignon;R. Guida;F. Hahn;E. Holzer;B. Jenninger;M. Koval;P. Laycock;G. Miotto;P. Lichard;A. Mapelli;R. Marchevski;K. Massri;M. Noy;V. Palladino;M. Perrin-Terrin;J. Pinzino;V. Ryjov;S. Schuchmann;S. Venditti;T. Bache;M. Brunetti;V. Duk;V. Fascianelli;J. Fry;F. Gonnella;E. Goudzovski;J. Henshaw;L. Iacobuzio;C. Lazzeroni;N. Lurkin;F. Newson;C. Parkinson;A. Romano;A. Sergi;A. Sturgess;J. Swallow;H. Heath;R. Page;S. Trilov;B. Angelucci;D. Britton;C. Graham;D. Protopopescu;J. Carmignani;J. Dainton;R. Jones;G. Ruggiero;L. Fulton;D. Hutchcroft;E. Maurice;B. Wrona;A. Conovaloff;P. Cooper;D. Coward;P. Rubin

Search for Lepton Number and Flavor Violation in K+ and π0 Decays

搜索 K 和 Ï0 衰变中的轻子数和味道违规

• DOI: 10.1103/physrevlett.127.131802
• 发表时间: 2021
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Aliberti, R.;Ambrosino, F.;Ammendola, R.;Angelucci, B.;Antonelli, A.;Anzivino, G.;Arcidiacono, R.;Bache, T.;Baeva, A.;Baigarashev, D.
• 通讯作者: Baigarashev, D.

Search for heavy neutral lepton production in K+ decays

• DOI: 10.1016/j.physletb.2018.01.031
• 发表时间: 2017-12
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: NA48 collaboration

Search for K+ decays to a muon and invisible particles

寻找 K 衰变为 μ 子和不可见粒子

• DOI: 10.1016/j.physletb.2021.136259
• 发表时间: 2021
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: Cortina Gil, E.;Kleimenova, A.;Minucci, E.;Padolski, S.;Petrov, P.;Shaikhiev, A.;Volpe, R.;Numao, T.;Petrov, Y.;Velghe, B.
• 通讯作者: Velghe, B.