J. M. De Miranda
A5022330468- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Nuclear physics research studies
- Superconducting Materials and Applications
- Medical Imaging Techniques and Applications
- Computational Physics and Python Applications
- Particle accelerators and beam dynamics
- Radiation Detection and Scintillator Technologies
- Stochastic processes and statistical mechanics
- International Science and Diplomacy
- Distributed and Parallel Computing Systems
- Advanced NMR Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Finite Group Theory Research
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Coding theory and cryptography
- Advanced Data Storage Technologies
Centro Brasileiro de Pesquisas Físicas
2009-2025
Purdue University West Lafayette
2025
Brazilian Center for Research in Energy and Materials
2025
University of California, Davis
1995-2007
Universidade Federal do Ceará
2002-2004
Universidade de São Paulo
2004
Bank of Mexico
2003
Universidad Nacional Autónoma de México
2001
University of Buenos Aires
1996-1998
Universidad de Los Andes
1995-1998
From a sample of 848+/-44 D(+)(s)-->pi(-)pi(+)pi(+) decays, we find gamma(D(+)(s)-->pi(-)pi(+)pi(+))/gamma(D(+)(s)-->straight phipi(+)) = 0.245+/-0.028(+0.019)(-0.012). Using Dalitz plot analysis this three body decay, significant contributions from the channels rho(0)(770)pi(+), rho(0)(1450)pi(+), f(0)(980)pi(+), f(2)(1270)pi(+), and f(0)(1370)pi(+). We also present values obtained for masses widths resonances f(0)(980) f(0)(1370).
Using data from the FOCUS experiment we analyze $D^+π^-$ and $D^0π^+$ invariant mass distributions. We measure $D_2^{*0}$ $M_{D_2^{*0}} = (2464.5 \pm 1.1 1.9) \mev$ width $Γ_{D_2^{*0}} (38.7 5.3 2.9) \mev$, $D_2^{*+}$ $ M_{D_2^{*+}} (2467.6 1.5 0.76) Γ_{D_2^{*+}} (34.1 6.5 4.2) \mev$. find evidence for broad structures over background in both neutral charged final state. If each is interpreted as a single L=1, $j_q=1/2$ excited charm meson resonance, masses widths are $M_{1/2}^0 =(2407 21...
We have performed a search for CPT violation in neutral charm meson oscillations. While flavor mixing the sector is predicted to be small by Standard Model, it still possible investigate through study of proper time dependence asymmetry right-sign decay rates $D^0\to K^-π^+$ and $\d0b\to K^+π^-$. This related violating complex parameter $ξ$ parameters $x$ $y$: $A_{CPT}\propto{\rm Re} ξy-{\rm Im} ξx$ . Our 95% confidence level limit $-0.0068
We present the first direct measurements of pion valence-quark momentum distribution which is related to square light-cone wave function. The were carried out using data on diffractive dissociation $500\mathrm{GeV}/c$ ${\ensuremath{\pi}}^{\ensuremath{-}}$ into dijets from a platinum target at Fermilab experiment E791. results show that $|q\overline{q}〉$ asymptotic function describes well for ${Q}^{2}\ensuremath{\sim}10(\mathrm{GeV}/c{)}^{2}$ or more. also measured transverse dijets.
We describe a novel use of the Dalitz plot to probe $CP$ symmetry in three-body modes $B$ and $D$ mesons. It is based on an observable inspired by astronomers' practice, namely significance difference between corresponding bins. provides model-independent mapping local asymmetries. illustrate method for probing two complementary cases decays: former sizable or even large effects can be expected, yet have differentiated against leading standard model contributions, while latter one cannot...
We have studied the diffractive dissociation into dijets of 500 GeV/c pions scattering coherently from carbon and platinum targets. Extrapolating to asymptotically high energies (where t(min)-->0), we find that when per-nucleus cross section for this process is parametrized as sigma = sigma0Aalpha, alpha has values near 1.6, exact result depending on jet transverse momentum. These are in agreement with those predicted by theoretical calculations color-transparency.
We measure forward cross sections for production of ${D}^{+}$, ${D}^{0}$, ${D}_{s}$, ${D}^{*+}$, and ${\ensuremath{\Lambda}}_{c}$ in collisions ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ifmmode\pm\else\textpm\fi{}}$, $p$ on a nuclear target. Production induced by different beam particles is found to be the same within statistics. Strange baryonic final states are seen contribute appreciably total charm section, which our measurements indicate larger than but consistent with...
A leading charm meson is one with longitudinal momentum fraction, xF>0, whose light quark (or antiquark) of the same type as quarks in beam particles. We report on production asymmetry, A=[σ(leading-σ(nonleading)]/[σ(leading)+σ(nonleading)] a function xF. The data consist 1500 fully reconstructed D± and D*± decays Fermilab experiment E 769. find significant asymmetry for not expected perturbative quantum chromodynamics.Received 22 October...
Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we report first directly measured constraint on decay-width difference Delta Gamma for mass eigenstates of D0-D0bar system. We obtain our result from lifetime measurements decays D0 --> K-pi+ and K-K+, under assumption CP invariance, which implies that are same. The K-K+ (the CP-even final state is \tau_KK = 0.410 +/- 0.011 0.006 ps, (an equal mixture CP-odd states tau_Kpi 0.413 0.003 0.004 ps. 2(Gamma_KK -...
Using data collected by the high-energy photoproduction experiment FOCUS at Fermilab we performed a Dalitz plot analysis of Cabibbo favored decay D+→K−π+π+. This study uses 53653 Dalitz-plot events with signal fraction ∼97%, and represents highest statistics, most complete for this channel. Results are presented discussed using two different formalisms. The first is simple sum Breit–Wigner functions freely fitted masses widths. It model traditionally adopted serves as comparison already...
We measure the differential cross sections with respect to Feynman $x$ ( ${x}_{F}$) and transverse momentum ${p}_{T}$) for $\ensuremath{\pi}$, $K$, $p$-induced charm meson production using fully reconstructed ${D}^{+}$, ${D}^{0}$, ${D}_{s}$ decays. The shapes of these are compared theoretical predictions quark next-to-leading order perturbative QCD modern parametrizations pion nucleon parton distributions. observe differences expected in induced by projectiles different gluon distributions,...
We report the result of a search for D0 - D0_bar mixing in data from hadroproduction experiment E791 at Fermilab. use D* tag and semileptonic decay vertices to look wrong-sign decays with time dependence.
We measure the relative cross sections for D mesons produced in interactions of ${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$ and ${\mathrm{\ensuremath{\pi}}}^{+}$ beams with targets Be, Cu, Al, W. The measurement is based on 1400 fully reconstructed decays types ${\mathit{D}}^{0}$\ensuremath{\rightarrow}${\mathit{K}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\pi}}}^{+}$,...
Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the $K^-\pi^+$ S-wave amplitude decay $D^+ \to K^-\pi^+\pi^+$. The is generic complex function to be determined directly fit. P- and D-waves are parameterized by sum Breit-Wigner amplitudes. measurement covers whole elastic range system.
We present results of a search for D0-D0bar mixing and doubly-Cabibbo-suppressed decays the D0 in Fermilab experiment E791, fixed-target charm hadroproduction experiment. look evidence decay chain D* -> pi (K or K pi). If charge pion from is same as kaon D (a ``wrong-sign'' event), may have occurred. Mixing can be distinguished other sources wrong-sign events (such decays) by analyzing distribution times. see no mixing. Allowing possible CP violation, our r_{mix}, ratio mixed to unmixed...
Using data from the FOCUS (E831) experiment, we have searched for T violation in charm meson decays using four-body decay channels D0→K−K+π−π+, D+→KS0K+π−π+, and Ds+→KS0K+π−π+. The asymmetry is obtained triple-product correlations assuming validity of CPT theorem. We find values to be ATviol(D0)=0.010±0.057(stat.)±0.037(syst.), ATviol(D+)=0.023±0.062(stat.)±0.022(syst.), ATviol(Ds+)=−0.036±0.067(stat.)±0.023(syst.). Each measurement consistent with no violation. New measurements CP...
We report results of the first search for pentaquark P_{{c bar}s} which is predicted to be a doublet states: P^0_{{c bar}s}=({c bar} s u d) and P^-_{{c d u). A was made decay --> phi,pi,p in data from Fermilab experiment E791, 500 GeV/c pi^- beam interacted with nuclear targets. present upper limits at 90% confidence level ratio cross section times branching fraction this that D_s phi,pi. The are 0.031 0.063 M(P^0_{{c bar}s}) = 2.75 2.86 GeV/c^2, respectively, assuming lifetime 0.4 ps.