We report the branching ratios of the ${\ensuremath{\chi}}_{c2}{(1}^{3}{P}_{2})$ and ${\ensuremath{\chi}}_{c0}{(1}^{3}{P}_{0})$ charmonium resonances to two photons using event samples collected by Fermilab experiment E835 in the reactions $\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\chi}}_{c2}{(1}^{3}{P}_{2})[{\ensuremath{\chi}}_{c0}{(1}^{3}{P}_{0})].$ Our result for the ${\ensuremath{\chi}}_{c2}$ is $B({\ensuremath{\chi}}_{c2}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})=(1.35\ifmmode\pm\else\textpm\fi{}0.25\ifmmode\pm\else\textpm\fi{}0.12)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$ We set a 95% upper limit for the ${\ensuremath{\chi}}_{c0}$ branching ratio $B({\ensuremath{\chi}}_{c0}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})$ at $2.09\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$

10.1103/physrevd.62.052002

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Citations (30)

Measurement of the $K^+\to\pi^+\gamma\gamma$ decay

HAL (Le Centre pour la Communication Scientifique Directe) (2023)

E. Cortina E. Minucci S. Padolski Plamen Petrov B. Velghe

Source

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Real-time optical tracking for motion compensated irradiation with scanned particle beams at CNAO

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2016)

Giovanni Fattori Matteo Seregni Andrea Pella Marco Riboldi L. Capasso

Motion simulator

Tracking (education)

10.1016/j.nima.2016.04.066

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Citations (16)

Observation of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay and measurement of its branching ratio

arXiv (Cornell University) (2024)

E. Cortina J. Jerhot N. Lurkin D. Bryman Toshio Numao

A measurement of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay by the NA62 experiment at the CERN SPS is presented, using data collected in 2021 and 2022. This dataset was recorded, after modifications to the beamline and detectors, at a higher instantaneous beam intensity with respect to the 2016--2018 data taking. Combining NA62 data collected in 2016--2022, a measurement of $B(K^{+}\rightarrow\pi^{+}\nu\bar{\nu}) = \left( 13.0^{+ 3.3}_{- 3.0} \right)\times10^{-11}$ is reported. With $51$ signal candidates observed and an expected background of $18^{+3}_{-2}$ events, $B(K^{+}\rightarrow\pi^{+}\nu\bar{\nu})$ becomes the smallest branching ratio measured with a signal significance above $5\,\sigma$.

Bar (unit)

Branching fraction

Branching (polymer chemistry)

Sigma

10.48550/arxiv.2412.12015

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EP-1594: On-line analysis of 4D treatment deliveries for scanned proton and carbon ion beams

Radiotherapy and Oncology (2016)

S. Giordanengo V. Monaco A. Attili A. Vignati Mohammad Varasteh Anvar

Line (geometry)

Carbon fibers

10.1016/s0167-8140(16)32844-4

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Citations (1)

A glass spherical Cherenkov counter based on total internal reflection

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (1990)

C. Biino A. Ceccucci R. Cester F. Marchetto E. Menichetti

Reflection

Particle identification

Cherenkov detector

10.1016/0168-9002(90)90428-9

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Citations (3)

Charmonium spectroscopy in p̄p annihilations

AIP conference proceedings (1992)

T. A. Armstrong D. Bettoni V. Bharadwaj C. Biino G. Borreani

This paper presents the experimental status of charmonium spectroscopy and describes the technique of c̄c formation in p̄p annihilations used by the experiment E760 at Fermilab. Results from 1990 data taking are reported.

Fermilab

Gamma Spectroscopy

10.1063/1.41627

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Measurement of the very rare K+ → $$ {\pi}^{+}\nu \overline{\nu} $$ decay

Journal of High Energy Physics (2021)

E. Cortina A. Kleimenova E. Minucci S. Padolski P. Petrov

A bstract The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} $$ BR K + → π + ν ν ¯ = 10.6 − 3.4 + 4.0 stat ± 0.9 syst × 10 − 11 at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016–2018. This provides evidence for the very rare K + → $$ {\pi}^{+}\nu \overline{\nu} $$ π + ν ν ¯ decay, observed with a significance of 3.4 σ . The experiment achieves a single event sensitivity of (0 . 839 ± 0 . 054) × 10 − 11 , corresponding to 10.0 events assuming the Standard Model branching ratio of (8 . 4 ± 1 . 0) × 10 − 11 . This measurement is also used to set limits on BR( K + → π + X ), where X is a scalar or pseudo-scalar particle. Details are given of the analysis of the 2018 data sample, which corresponds to about 80% of the total data sample.

Overline

10.1007/jhep06(2021)093

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Citations (115)

Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in antiproton-proton annihilations

arXiv (Cornell University) (2007)

Fermilab E Collaboration M. Andreotti S. Bagnasco W. Baldini D. Bettoni

We present new precision measurements of the psi(2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the psi(2S) meson through the processes pbar p -> e+ e- and pbar p -> J/psi + X -> e+ e- + X. We measure the width to be Gamma = 290 +- 25(sta) +- 4(sys) keV and the combination of partial widths Gamma_e+e- * Gamma_pbarp / Gamma = 579 +- 38(sta) +- 36(sys) meV, which represent the most precise measurements to date.

Antiproton

Fermilab

Annihilation

10.48550/arxiv.hep-ex/0703012

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