P. Chang

ORCID: 0000-0003-4064-388X
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Research Areas
  • Particle physics theoretical and experimental studies
  • High-Energy Particle Collisions Research
  • Quantum Chromodynamics and Particle Interactions
  • Particle Detector Development and Performance
  • Dark Matter and Cosmic Phenomena
  • Neutrino Physics Research
  • Cosmology and Gravitation Theories
  • Computational Physics and Python Applications
  • Particle Accelerators and Free-Electron Lasers
  • Black Holes and Theoretical Physics
  • Medical Imaging Techniques and Applications
  • Superconducting Materials and Applications
  • Astrophysics and Cosmic Phenomena
  • Nuclear physics research studies
  • Atomic and Subatomic Physics Research
  • Radiation Detection and Scintillator Technologies
  • Distributed and Parallel Computing Systems
  • Particle accelerators and beam dynamics
  • Gamma-ray bursts and supernovae
  • Advanced NMR Techniques and Applications
  • Geophysical and Geoelectrical Methods
  • Radioactive Decay and Measurement Techniques
  • Scientific Computing and Data Management
  • Radiation Therapy and Dosimetry
  • Nuclear reactor physics and engineering

National Taiwan University
2015-2024

University of California, San Diego
2018-2024

Institute of High Energy Physics
2012-2024

University of Antwerp
2024

A. Alikhanyan National Laboratory
2022-2024

University of Florida
1997-2024

University of California System
2024

Istituto Nazionale di Fisica Nucleare
2000-2023

National Central University
2006-2023

Massachusetts Institute of Technology
2001-2023

We report the observation of a narrow charmoniumlike state produced in exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has mass 3872.0+/-0.6(stat)+/-0.5(syst) MeV, value that is very near M(D0)+M(D(*0)) threshold. The results are based on an analysis 152M B-Bmacr; events collected at Upsilon(4S) resonance Belle detector KEKB collider. signal statistical significance excess 10sigma.

10.1103/physrevlett.91.262001 article EN Physical Review Letters 2003-12-23

The cross section for ee+ e- → π+ π- J/ψ between 3.8 and 5.5 GeV is measured with a 967 fb(-1) data sample collected by the Belle detector at or near Υ(nS) (n = 1,2,…,5) resonances. Y(4260) state observed, its resonance parameters are determined. In addition, an excess of production around 4 observed. This feature can be described Breit-Wigner parametrization properties that consistent Y(4008) was previously reported Belle. study decays, structure observed in M(π(±)J/ψ) mass spectrum 5.2σ...

10.1103/physrevlett.110.252002 article EN publisher-specific-oa Physical Review Letters 2013-06-17

We report a measurement of the branching fraction ratios R(D(*)) Bbar -> D(*) tau- nubar_tau relative to D()* l- nubar_l (where l = e or mu) using full Belle data sample 772 x 10^6 BBbar pairs collected at Y(4S) resonance with detector KEKB asymmetric-energy e+e- collider. The measured values are R(D)= 0.375 +- 0.064(stat.) 0.026(syst.) and R(D*) 0.293 0.038(stat.) 0.015(syst.). analysis uses hadronic reconstruction tag-side B meson purely leptonic tau decays. results consistent earlier...

10.1103/physrevd.92.072014 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2015-10-26

We report the observation of two narrow structures in mass spectra pi+-Y(nS) (n=1,2,3) and pi+-hb(mP)(m$ (m=1,2) pairs that are produced association with a single charged pion Y(5S) decays. The measured masses widths averaged over five final states M_1=(10607.2+-2.0) MeV/c2, Gamma_1=(18.4+-2.4) MeV M_2=(10652.2+-1.5) Gamma_2=(11.5+-2.2) MeV. results obtained 121.4 1/fb data sample collected Belle detector vicinity resonance at KEKB asymmetric-energy e+e- collider.

10.1103/physrevlett.108.122001 article EN publisher-specific-oa Physical Review Letters 2012-03-20

We present a measurement of the standard model $\mathrm{CP}$ violation parameter $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ based on $29.1{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected at $\ensuremath{\Upsilon}(4S)$ resonance with Belle detector KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral $B$ meson is fully reconstructed as $J/\ensuremath{\psi}{K}_{S}$, $\ensuremath{\psi}(2S){K}_{S}$, ${\ensuremath{\chi}}_{c1}{K}_{S}$, ${\ensuremath{\eta}}_{c}{K}_{S}$,...

10.1103/physrevlett.87.091802 article EN Physical Review Letters 2001-08-14

A distinct peak is observed in the ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\psi}}^{\ensuremath{'}}$ invariant mass distribution near 4.43 GeV $B\ensuremath{\rightarrow}K{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\psi}}^{\ensuremath{'}}$ decays. fit using a Breit-Wigner resonance shape yields and width of $M=4433\ifmmode\pm\else\textpm\fi{}4(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}$...

10.1103/physrevlett.100.142001 article EN Physical Review Letters 2008-04-08

We report the first measurement of $\ensuremath{\tau}$ lepton polarization ${P}_{\ensuremath{\tau}}({D}^{*})$ in decay $\overline{B}\ensuremath{\rightarrow}{D}^{*}{\ensuremath{\tau}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\tau}}$ as well a new ratio branching fractions...

10.1103/physrevlett.118.211801 article EN publisher-specific-oa Physical Review Letters 2017-05-26

We study B→K(*)ℓ+ℓ− decays (ℓ=e, μ) based on a data sample of 657×106 BB¯ pairs collected with the Belle detector at KEKB e+e− collider. report differential branching fraction, isospin asymmetry, K* polarization, and forward-backward asymmetry (AFB) as functions q2=Mℓℓ2c2. The fitted AFB spectrum exceeds standard model expectation by 2.7 deviations. measured fractions are B(B→K*ℓ+ℓ−)=(10.7−1.0+1.1±0.9)×10−7 B(B→Kℓ+ℓ−)=(4.8−0.4+0.5±0.3)×10−7, where first errors statistical second systematic,...

10.1103/physrevlett.103.171801 article EN Physical Review Letters 2009-10-20

This work is on the Physics of B Factories. Part A this book contains a brief description SLAC and KEK Factories as well their detectors, BaBar Belle, data taking related issues. discusses tools methods used by experiments in order to obtain results. The results themselves can be found C. Please note that version 3 archive auxiliary book. uses notation alpha, beta, gamma for angles Unitarity Triangle. nominal phi_1, phi_2 phi_3. cite Eur. Phys. J. C74 (2014) 3026.

10.1140/epjc/s10052-014-3026-9 article EN cc-by The European Physical Journal C 2014-11-01

The cross section for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\psi}(2S)$ between threshold and $\sqrt{s}=5.5\text{ }\text{ }\mathrm{GeV}$ is measured using $673\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data on off the $\ensuremath{\Upsilon}(4S)$ resonance collected with Belle detector at KEKB. Two resonant structures are observed in...

10.1103/physrevlett.99.142002 article EN Physical Review Letters 2007-10-01

We report a measurement of the ratio ${\cal R}(D^*) = {\cal B}(\bar{B}^0 \rightarrow D^{*+} \tau^- \bar{\nu}_{\tau})/{\cal \ell^- \bar{\nu}_{\ell})$, where $\ell$ denotes an electron or muon. The results are based on data sample containing $772\times10^6$ $B\bar{B}$ pairs recorded at $\Upsilon(4S)$ resonance with Belle detector KEKB $e^+ e^-$ collider. select $B^0 \bar{B}^0$ by reconstructing both $B$ mesons in semileptonic decays to $D^{*\mp} \ell^{\pm}$. measure R}(D^*)= 0.302 \pm...

10.1103/physrevd.94.072007 article EN publisher-specific-oa Physical review. D/Physical review. D. 2016-10-27

The cross section for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$ between 3.8 and $5.5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is measured using a $548\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected on or near the $\ensuremath{\Upsilon}(4S)$ resonance with Belle detector at KEKB. A peak $4.25\text{ }\mathrm{GeV}/{c}^{2}$, corresponding to so called $Y(4260)$, observed. In addition, there another...

10.1103/physrevlett.99.182004 article EN Physical Review Letters 2007-11-02

The Belle experiment, running at the KEKB e+e− asymmetric energy collider during first decade of century, achieved its original objective precisely measuring differences between particles and antiparticles in B system. After collecting 1000 fb−1 data various Υ resonances, also obtained many other physics results described this article.

10.1093/ptep/pts072 article EN cc-by Progress of Theoretical and Experimental Physics 2012-12-29

We present a measurement of angular observables and test lepton flavor universality in the $B\ensuremath{\rightarrow}{K}^{*}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ decay, where $\ensuremath{\ell}$ is either $e$ or $\ensuremath{\mu}$. The analysis performed on data sample corresponding to an integrated luminosity $711\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ containing $772\ifmmode\times\else\texttimes\fi{}1{0}^{6}$ $B\overline{B}$ pairs, collected at...

10.1103/physrevlett.118.111801 article EN publisher-specific-oa Physical Review Letters 2017-03-13

The experimental results on the ratios of branching fractions R(D)=B(B[over ¯]→Dτ^{-}ν[over ¯]_{τ})/B(B[over ¯]→Dℓ^{-}ν[over ¯]_{ℓ}) and R(D^{*})=B(B[over ¯]→D^{*}τ^{-}ν[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}), where ℓ denotes an electron or a muon, show long-standing discrepancy with standard model predictions, might hint at violation lepton flavor universality. We report new simultaneous measurement R(D) R(D^{*}), based data sample containing 772×10^{6} BB[over ¯] events recorded ϒ(4S) resonance...

10.1103/physrevlett.124.161803 article EN cc-by Physical Review Letters 2020-04-24

With the full data sample of $772 \times 10^6$ $B{\bar B}$ pairs recorded by Belle detector at KEKB electron-positron collider, decay $\bar{B} \rightarrow D^* \tau^- \bar{\nu}_\tau$ is studied with hadronic $\tau$ decays $\tau^- \pi^- \nu_\tau$ and \rho^- \nu_\tau$. The polarization $P_\tau(D^*)$ in two-body measured, as well ratio branching fractions $R(D^{*}) = \mathcal{B}(\bar {B} \bar{\nu}_\tau) / \mathcal{B}(\bar{B} \ell^- \bar{\nu}_\ell)$, where $\ell^-$ denotes an electron or a muon....

10.1103/physrevd.97.012004 article EN cc-by Physical review. D/Physical review. D. 2018-01-10

We present measurements of the branching fractions for decays $B\to K \mu^{+}\mu^{-}$ and e^{+}e^{-}$, their ratio ($R_{K}$), using a data sample 711 $fb^{-1}$ that contains $772 \times 10^{6}$ $B\bar{B}$ events. The were collected at $\Upsilon(4S)$ resonance with Belle detector KEKB asymmetric-energy $e^{+}e^{-}$ collider. $R_{K}$ is measured in five bins dilepton invariant-mass-squared ($q^{2}$): $q^{2} \in (0.1, 4.0), (4.0, 8.12), (1.0, 6.0)$, $(10.2, 12.8)$ ($>14.18) GeV^{2}/c^{4}$,...

10.1007/jhep03(2021)105 article EN cc-by Journal of High Energy Physics 2021-03-01

Abstract A multi-TeV muon collider offers a spectacular opportunity in the direct exploration of energy frontier. Offering combination unprecedented collisions comparatively clean leptonic environment, high has unique potential to provide both precision measurements and highest reach one machine that cannot be paralleled by any currently available technology. The topic generated lot excitement Snowmass meetings continues attract large number supporters, including many from early career...

10.1088/1748-0221/19/02/t02015 article EN cc-by Journal of Instrumentation 2024-02-01

We search for the rare decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>B</a:mi><a:mo>+</a:mo></a:msup><a:mo stretchy="false">→</a:mo><a:msup><a:mi>K</a:mi><a:mo>+</a:mo></a:msup><a:mi>ν</a:mi><a:mover accent="true"><a:mi>ν</a:mi><a:mo stretchy="false">¯</a:mo></a:mover></a:math> in a <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mn>362</f:mn><f:mtext> </f:mtext><f:mtext>...

10.1103/physrevd.109.112006 article EN cc-by Physical review. D/Physical review. D. 2024-06-06

We report the observation of a near-threshold enhancement in omegaJ/psi invariant mass distribution for exclusive B-->KomegaJ/psi decays. The results are obtained from 253 fb(-1) data sample that contains 275 x 10(6) BB pairs were collected near Upsilon(4S) resonance with Belle detector at KEKB asymmetric energy e(+)e(-) collider. statistical significance is estimated to be greater than 8sigma.

10.1103/physrevlett.94.182002 article EN Physical Review Letters 2005-05-12

We have observed bottom-charm mesons B_c via the decay mode Bc -> J/psi lepton neutrino in 1.8 TeV p-bar p collisions using CDF detector at Fermilab Tevatron. A fit of background and signal contributions to + mass distribution yielded 20.4 +6.2 -5.5 events from mesons. same with alone was rejected level 4.8 standard deviations. measured be 6.40 +- 0.39 0.13 GeVc^2 lifetime tau(B_c) = 0.46 +0.18 -0.16 0.03 ps. production cross section times branching ratio for relative that B+ K 0.132 +0.041...

10.1103/physrevlett.81.2432 article EN Physical Review Letters 1998-09-21

We present a study of $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)$ production in $p\overline{p}$ collisions, at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ with the CDF detector Fermilab. The mesons are reconstructed using their ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ decay modes. have measured inclusive cross section for both as function transverse momentum central region, $|\ensuremath{\eta}|<0.6$. also measure fraction these events...

10.1103/physrevlett.79.572 article EN Physical Review Letters 1997-07-28
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