Search NASA⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 2336583

Spin density matrix elements in exclusive $\rho ^0$ meson muoproduction

Alexeev, G. D. (ORCID:0009000701968178)·Alexeev, M. G. (ORCID:0000000273068255)·Alice, C. (ORCID:0000000162979857)·Amoroso, A. (ORCID:0000000230958610)·Andrieux, V. (ORCID:0000000199579910)·Anosov, V. (ORCID:0009000335959561)·Augsten, K. (ORCID:0000000183240576)·Augustyniak, W.·Azevedo, C. R. (ORCID:0000000200129918)·Badelek, B. (ORCID:0000000240821466)·Barth, J. (ORCID:0009000308919935)·Beck, R.·Bedfer, Y. (ORCID:0000000251981852)·Bernhard, J. (ORCID:000000019256971X)·Bodlak, M.·Bradamante, F. (ORCID:000000016136376X)·Bressan, A. (ORCID:0000000237186377)·Burtsev, V. E.·Chang, W. -C. (ORCID:0000000216957830)·Chatterjee, C. (ORCID:0000000177843792)·Chiosso, M. (ORCID:0000000169948551)·Chumakov, A. G. (ORCID:0000000260122435)·Chung, Suh-urk·Cicuttin, A. (ORCID:0000000236459791)·Correia, P. M. (ORCID:0000000172927735)·Crespo, M. L. (ORCID:0000000254833388)·D’Ago, D. (ORCID:0000000218376351)·Torre, S. Dalla (ORCID:0000000255529732)·Dasgupta, S. S. (ORCID:0000000343193394)·Dasgupta, S.·Carro, F. Del (ORCID:0000000176365493)·Denisenko, I. (ORCID:0000000244081565)·Denisov, O. Yu. (ORCID:000000021057058X)·Donskov, S. V. (ORCID:0000000239887687)·Doshita, N. (ORCID:0000000221292511)·Dreisbach, Ch (ORCID:0009000155654314)·Dünnweber, W. (ORCID:0009000755980332)·Dusaev, R. R. (ORCID:0000000261478038)·Ecker, D. (ORCID:0000000329822713)·Efremov, A.·Eremeev, D.·Faccioli, P. (ORCID:0000000318496692)·Faessler, M.·Finger, M. (ORCID:0000000278289970)·Finger, M. (ORCID:0000000331552484)·Fischer, H. (ORCID:0000000293427665)·Flöthner, K. J. (ORCID:0000000240526838)·Florian, W. (ORCID:0000000229513059)·Friedrich, J. M. (ORCID:0000000192987882)·Frolov, V. (ORCID:0009000518840264)·Garcia Ordòñez, L. G. (ORCID:000000030712413X)·Gautheron, F.·Gavrichtchouk, O. P. (ORCID:0000000283839631)·Gerassimov, S. (ORCID:0000000177808735)·Giarra, J. (ORCID:0009000569765604)·Giordano, D. (ORCID:0000000302289226)·Gorzellik, M. (ORCID:0009000014235896)·Grasso, A.·Gridin, A. (ORCID:0000000295818600)·Perdekamp, M. Grosse (ORCID:0000000227115217)·Grube, B. (ORCID:0000000184730454)·Grüner, M. (ORCID:0009000463179527)·Guskov, A. (ORCID:0000000185321900)·Harrach, D. von·Hoffmann, M. (ORCID:0009000708472730)·Horikawa, N.·d’Hose, N. (ORCID:0009000781049365)·Hsieh, C. -Y. (ORCID:0009000239681985)·Huber, S.·Ishimoto, S. (ORCID:0009000920792328)·Ivanov, A.·Iwata, T. (ORCID:0000000186011322)·Jandek, M.·Jary, V. (ORCID:0000000347184444)·Joosten, R. (ORCID:0009000590460119)·Kabuß, E. (ORCID:0000000213716361)·Kaspar, F. (ORCID:0009000859960264)·Kerbizi, A. (ORCID:0000000263968735)·Ketzer, B. (ORCID:0000000234933891)·Khatun, A. (ORCID:000000022724668X)·Khaustov, G. V. (ORCID:0009000867043167)·Klein, F.·Koivuniemi, J. H. (ORCID:0000000268175267)·Kolosov, V. N. (ORCID:0009000559946372)·Horikawa, K. Kondo (ORCID:0009000496922057)·Konorov, I. (ORCID:0000000290135456)·Konstantinov, V. F.·Korzenev, A. M. (ORCID:0000000321074415)·Kotzinian, A. M. (ORCID:0000000183263284)·Kouznetsov, O. M. (ORCID:0000000218211477)·Koval, A.·Kral, Z. (ORCID:0000000310427588)·Krinner, F.·Kunne, F.·Kurek, K. (ORCID:0000000212982078)·Kurjata, R. P. (ORCID:000000018547910X)·Kveton, A. (ORCID:0000000181971914)·Lavickova, K. (ORCID:0000000177032316)·Levorato, S. (ORCID:0000000180675355)·Lian, Y. -S. (ORCID:0000000162224454)
View original source ↗Read source document ↗Export metadata ↓

Abstract

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $\rho ^0$ meson muoproduction at COMPASS using 160 GeV/c polarised μ + and μ – beams impinging on a liquid hydrogen target. The measurement covers the kinematic range 5.0 GeV/c 2 < W < 17.0 GeV/c 2 , 1.0 (GeV/c) 2 < $\mathrm{Q}$ 2 < 10.0 (GeV/c) 2 and 0.01 (GeV/c) 2 < $p_{\textrm{T}}^2$ < 0.5 (GeV/c) 2 . Here, W denotes the mass of the final hadronic system, $\mathrm{Q}$ 2 the virtuality of the exchanged photon, and $p_{\textrm{T}}$ the transverse momentum of the $\rho ^0$ meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons ($\gamma ^*_T \rightarrow V^{ }_L$) indicate a violation of s-channel helicity conservation. Additionally, we observe a dominant contribution of natural-parity-exchange transitions and a very small contribution of unnatural-parity-exchange transitions, which is compatible with zero within experimental uncertainties. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow one to evaluate in a model-dependent way the role of parton helicity-flip GPDs in exclusive $\rho ^0$ production.

Explore related subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Alexeev, G. D. (ORCID:0009000701968178), Alexeev, M. G. (ORCID:0000000273068255), Alice, C. (ORCID:0000000162979857), Amoroso, A. (ORCID:0000000230958610), Andrieux, V. (ORCID:0000000199579910), Anosov, V. (ORCID:0009000335959561), Augsten, K. (ORCID:0000000183240576), Augustyniak, W., Azevedo, C. R. (ORCID:0000000200129918), Badelek, B. (ORCID:0000000240821466), Barth, J. (ORCID:0009000308919935), Beck, R., Bedfer, Y. (ORCID:0000000251981852), Bernhard, J. (ORCID:000000019256971X), Bodlak, M., Bradamante, F. (ORCID:000000016136376X), Bressan, A. (ORCID:0000000237186377), Burtsev, V. E., Chang, W. -C. (ORCID:0000000216957830), Chatterjee, C. (ORCID:0000000177843792), Chiosso, M. (ORCID:0000000169948551), Chumakov, A. G. (ORCID:0000000260122435), Chung, Suh-urk, Cicuttin, A. (ORCID:0000000236459791), Correia, P. M. (ORCID:0000000172927735), Crespo, M. L. (ORCID:0000000254833388), D’Ago, D. (ORCID:0000000218376351), Torre, S. Dalla (ORCID:0000000255529732), Dasgupta, S. S. (ORCID:0000000343193394), Dasgupta, S., Carro, F. Del (ORCID:0000000176365493), Denisenko, I. (ORCID:0000000244081565), Denisov, O. Yu. (ORCID:000000021057058X), Donskov, S. V. (ORCID:0000000239887687), Doshita, N. (ORCID:0000000221292511), Dreisbach, Ch (ORCID:0009000155654314), Dünnweber, W. (ORCID:0009000755980332), Dusaev, R. R. (ORCID:0000000261478038), Ecker, D. (ORCID:0000000329822713), Efremov, A., Eremeev, D., Faccioli, P. (ORCID:0000000318496692), Faessler, M., Finger, M. (ORCID:0000000278289970), Finger, M. (ORCID:0000000331552484), Fischer, H. (ORCID:0000000293427665), Flöthner, K. J. (ORCID:0000000240526838), Florian, W. (ORCID:0000000229513059), Friedrich, J. M. (ORCID:0000000192987882), Frolov, V. (ORCID:0009000518840264), Garcia Ordòñez, L. G. (ORCID:000000030712413X), Gautheron, F., Gavrichtchouk, O. P. (ORCID:0000000283839631), Gerassimov, S. (ORCID:0000000177808735), Giarra, J. (ORCID:0009000569765604), Giordano, D. (ORCID:0000000302289226), Gorzellik, M. (ORCID:0009000014235896), Grasso, A., Gridin, A. (ORCID:0000000295818600), Perdekamp, M. Grosse (ORCID:0000000227115217), Grube, B. (ORCID:0000000184730454), Grüner, M. (ORCID:0009000463179527), Guskov, A. (ORCID:0000000185321900), Harrach, D. von, Hoffmann, M. (ORCID:0009000708472730), Horikawa, N., d’Hose, N. (ORCID:0009000781049365), Hsieh, C. -Y. (ORCID:0009000239681985), Huber, S., Ishimoto, S. (ORCID:0009000920792328), Ivanov, A., Iwata, T. (ORCID:0000000186011322), Jandek, M., Jary, V. (ORCID:0000000347184444), Joosten, R. (ORCID:0009000590460119), Kabuß, E. (ORCID:0000000213716361), Kaspar, F. (ORCID:0009000859960264), Kerbizi, A. (ORCID:0000000263968735), Ketzer, B. (ORCID:0000000234933891), Khatun, A. (ORCID:000000022724668X), Khaustov, G. V. (ORCID:0009000867043167), Klein, F., Koivuniemi, J. H. (ORCID:0000000268175267), Kolosov, V. N. (ORCID:0009000559946372), Horikawa, K. Kondo (ORCID:0009000496922057), Konorov, I. (ORCID:0000000290135456), Konstantinov, V. F., Korzenev, A. M. (ORCID:0000000321074415), Kotzinian, A. M. (ORCID:0000000183263284), Kouznetsov, O. M. (ORCID:0000000218211477), Koval, A., Kral, Z. (ORCID:0000000310427588), Krinner, F., Kunne, F., Kurek, K. (ORCID:0000000212982078), Kurjata, R. P. (ORCID:000000018547910X), Kveton, A. (ORCID:0000000181971914), Lavickova, K. (ORCID:0000000177032316), Levorato, S. (ORCID:0000000180675355), Lian, Y. -S. (ORCID:0000000162224454). 2023-10-13. Spin density matrix elements in exclusive $\rho ^0$ meson muoproduction. https://doi.org/10.1140/epjc%2Fs10052-023-11359-4

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

SMEFT ATLAS: The landscape beyond the Standard Model

The Standard Model Effective Field Theory (SMEFT) based on the unbroken gauge group SU(3) 𝐶 ⊗SU(2) 𝐿 ⊗U(1) 𝑌 and containing only particles of the Standard Model (SM) has developed in the last decade to a mature field. It is the framework to be used in the energy gap from scales sufficiently higher than the electroweak scale up to the lowest energy scale at which new particles show up. We summarize the present status of this theory with a particular emphasize on its role in the indirect search for new physics (NP). While flavour physics of both quarks and leptons is the main topic of our review, we also discuss electric dipole moments, anomalous magnetic moments (𝑔−2) 𝜇,𝑒 , 𝑍-pole observables, Higgs observables and high-𝑝𝑇 scattering processes within the SMEFT. We group the observables into ten classes and list for each class the most relevant operators and the corresponding renormalization group equations (RGEs). We exhibit the correlations between different classes implied both by the operator mixing and the SU(2) 𝐿 gauge symmetry. Our main goal is to provide an insight into the complicated operator structure of this framework which hopefully will facilitate the identification of valid ultraviolet completions behind possible anomalies observed in future data. Numerous colourful charts, and 85 tables, while representing rather complicated RG evolution from the NP scale down to the electroweak scale, beautify the involved SMEFT landscape. Over 1000 references to the literature underline the importance and the popularity of this field. We discuss both top-down and bottom-up approaches as well as their interplay. This allows us eventually to present an atlas of different landscapes beyond the SM that includes heavy gauge bosons and scalars, vector-like quarks and leptons and leptoquarks.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Exploring the Energy Frontier through Precision Tests and Fast Tracking with the CMS Detector (Final Technical Report)

This Early Career Award supported a research program using the CMS experiment at the CERN LHC to probe physics beyond the Standard Model in the top quark and Higgs boson sectors, alongside detector and trigger developments for the High-Luminosity LHC (HL-LHC) upgrade. The program (i) searched for charged lepton flavor violation (LFV) in the top quark sector with the full CMS Run-2 data set, placing the world’s strongest limits to date on the $t → eµq\ (q = u/c)$ branching fraction; (ii) developed preliminary analysis methods toward a boosted $t\bar{t}H(b\bar{b})$ measurement of the top quark Yukawa coupling and its CP properties; (iii) made leading contributions to the hardware-based Level-1 (L1) track finding system for the upgraded CMS detector for HL-LHC; and (iv) developed novel L1 trigger algorithms, notably a displaced vertex trigger enabling new searches for exotic long-lived particles.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Atmospheric pion, kaon, and muon fluxes for sub-orbital experiments

Cosmic rays interacting with the Earth's atmosphere generate extensive air showers, which produce Cherenkov, fluorescence and radio emissions. These emissions are key signatures for detection by ground-based, sub-orbital, and satellite-based telescopes aiming to study high energy cosmic ray and neutrino events. However, detectors operating at ground and balloon altitudes are also exposed to a background of atmospheric charged particles, primarily pions, kaons, and muons, that can mimic or obscure the signals from astrophysical sources. In this work, we use coupled cascade equations to calculate the atmospheric pion, kaon and muon fluxes reaching detectors at various altitudes. Our analysis focuses on energies above 10 GeV, where the influence of the Earth's magnetic field on particle trajectories is minimal. We provide angular and energy-resolved flux estimates and discuss their relevance as background for extensive air shower detection. Furthermore, our results are potentially relevant for interpreting data from current and future balloon-borne experiments such as EUSO-SPB2 and for refining trigger and veto strategies in Cherenkov and fluorescence telescopes.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗