COVID-19 therapy optimization by AI-driven biomechanical simulations

The COVID-19 disease causes pneumonia in many patients that in the most serious cases evolves into the Acute Distress Respiratory Syndrome (ARDS), requiring assisted ventilation and intensive care. In this context, identification of patients at high risk of developing ARDS is a key point for early clinical management, better clinical outcome and optimization in using the limited resources available in the intensive care units. We propose an AI-based prognostic system that makes predictions of oxygen exchange with arterial blood by using as input lung Computed Tomography (CT), the air flux in lungs obtained from biomechanical simulations and Arterial Blood Gas (ABG) analysis. We developed and investigated the feasibility of this system on a small clinical database of proven COVID-19 cases where the initial CT and various ABG reports were available for each patient. We studied the time evolution of the ABG parameters and found correlation with the morphological information extracted from CT scans and disease outcome. Promising results of a preliminary version of the prognostic algorithm are presented. The ability to predict the evolution of patients' respiratory efficiency would be of crucial importance for disease management.

A photogrammetric method for target monitoring inside the MEG II detector

An automatic target monitoring method based on photographs taken by a CMOS photo-camera has been developed for the MEG II detector. The technique could be adapted for other fixed-target experiments requiring good knowledge of their target position to avoid biases and systematic errors in measuring the trajectories of the outcoming particles. A CMOS-based, high resolution, high radiation tolerant, and high magnetic field resistant photo-camera was mounted inside the MEG II detector at the Paul Scherrer Institute (Switzerland). MEG II is used to search for lepton flavor violation in muon decays. The photogrammetric method's challenges, affecting measurements of low momentum particles' tracks, are the high magnetic field of the spectrometer, high radiation levels, tight space constraints, and the need to limit the material budget in the tracking volume. The camera is focused on the dot pattern drawn on the thin MEG II target, about 1 m away from the detector endcaps where the photo-camera is placed. Target movements and deformations are monitored by comparing images of the dots taken at various times during the measurement. The images are acquired with a Raspberry board and analyzed using custom software. Global alignment to the spectrometer is guaranteed by corner cubes placed on the target support. As a result, the target monitoring fulfills the needs of the experiment.

MR-based artificial intelligence model to assess response to therapy in locally advanced rectal cancer

PURPOSE

To develop and validate an Artificial Intelligence (AI) model based on texture analysis of high-resolution T2 weighted MR images able 1) to predict pathologic Complete Response (CR) and 2) to identify non-responders (NR) among patients with locally-advanced rectal cancer (LARC) after receiving neoadjuvant chemoradiotherapy (CRT).

METHOD

Fifty-five consecutive patients with LARC were retrospectively enrolled in this study. Patients underwent 3 T Magnetic Resonance Imaging (MRI) acquiring T2-weighted images before, during and after CRT. All patients underwent complete surgical resection and histopathology was the gold standard. Textural features were automatically extracted using an open-source software. A sub-set of statistically significant textural features was selected and two AI models were built by training a Random Forest (RF) classifier on 28 patients (training cohort). Model performances were estimated on 27 patients (validation cohort) using a ROC curve and a decision curve analysis.

RESULTS

Sixteen of 55 patients achieved CR. The AI model for CR classification showed good discrimination power with mean area under the receiver operating curve (AUC) of 0.86 (95% CI: 0.70, 0.94) in the validation cohort. The discriminatory power for the NR classification showed a mean AUC of 0.83 (95% CI: 0.71,0.92). Decision curve analysis confirmed higher net patient benefit when using AI models compared to standard-of-care.

CONCLUSIONS

AI models based on textural features of MR images of patients with LARC may help to identify patients who will show CR at the end of treatment and those who will not respond to therapy (NR) at an early stage of the treatment.

Secondary radiation measurements for particle therapy applications: charged particles produced by 4He and 12C ion beams in a PMMA target at large angle

Proton and carbon ion beams are used in the clinical practice for external radiotherapy treatments achieving, for selected indications, promising and superior clinical results with respect to x-ray based radiotherapy. Other ions, like [Formula: see text] have recently been considered as projectiles in particle therapy centres and might represent a good compromise between the linear energy transfer and the radiobiological effectiveness of [Formula: see text] ion and proton beams, allowing improved tumour control probability and minimising normal tissue complication probability. All the currently used p, [Formula: see text] and [Formula: see text] ion beams allow achieving sharp dose gradients on the boundary of the target volume, however the accurate dose delivery is sensitive to the patient positioning and to anatomical variations with respect to photon therapy. This requires beam range and/or dose release measurement during patient irradiation and therefore the development of dedicated monitoring techniques. All the proposed methods make use of the secondary radiation created by the beam interaction with the patient and, in particular, in the case of [Formula: see text] ion beams are also able to exploit the significant charged radiation component. Measurements performed to characterise the charged secondary radiation created by [Formula: see text] and [Formula: see text] particle therapy beams are reported. Charged secondary yields, energy spectra and emission profiles produced in a poly-methyl methacrylate (PMMA) target by [Formula: see text] and [Formula: see text] beams of different therapeutic energies were measured at 60° and 90° with respect to the primary beam direction. The secondary yield of protons produced along the primary beam path in a PMMA target was obtained. The energy spectra of charged secondaries were obtained from time-of-flight information, whereas the emission profiles were reconstructed exploiting tracking detector information. The obtained measurements are in agreement with results reported in the literature and suggests the feasibility of range monitoring based on charged secondary particle detection: the implications for particle therapy monitoring applications are also discussed.

Secondary radiation measurements for particle therapy applications: prompt photons produced by 4He, 12C and 16O ion beams in a PMMA target

Charged particle beams are used in particle therapy (PT) to treat oncological patients due to their selective dose deposition in tissues with respect to the photons and electrons used in conventional radiotherapy. Heavy (Z  >  1) PT beams can additionally be exploited for their high biological effectiveness in killing cancer cells. Nowadays, protons and carbon ions are used in PT clinical routines. Recently, interest in the potential application of helium and oxygen beams has been growing. With respect to protons, such beams are characterized by their reduced multiple scattering inside the body, increased linear energy transfer, relative biological effectiveness and oxygen enhancement ratio. The precision of PT demands online dose monitoring techniques, crucial to improving the quality assurance of any treatment: possible patient mis-positioning and biological tissue changes with respect to the planning CT scan could negatively affect the outcome of the therapy. The beam range confined in the irradiated target can be monitored thanks to the neutral or charged secondary radiation emitted by the interactions of hadron beams with matter. Among these secondary products, prompt photons are produced by nuclear de-excitation processes, and at present, different dose monitoring and beam range verification techniques based on prompt-γ detection are being proposed. It is hence of importance to perform γ yield measurement in therapeutic-like conditions. In this paper we report on the yields of prompt photons produced by the interaction of helium, carbon and oxygen ion beams with a poly-methyl methacrylate (PMMA) beam stopping target. The measurements were performed at the Heidelberg Ion-Beam Therapy Center (HIT) with beams of different energies. An LYSO scintillator, placed at [Formula: see text] and [Formula: see text] with respect to the beam direction, was used as the photon detector. The obtained γ yields for the carbon ion beams are compared with results from the literature, while no other results from helium and oxygen beams have been published yet. A discussion on the expected resolution of a slit camera detector is presented, demonstrating the feasibility of a prompt-γ-based monitoring technique for PT treatments using helium, carbon and oxygen ion beams.

A novel radioguided surgery technique exploiting β(-) decays

The background induced by the high penetration power of the radiation is the main limiting factor of the current radio-guided surgery (RGS). To partially mitigate it, a RGS with β⁺-emitting radio-tracers has been suggested in literature. Here we propose the use of β⁻-emitting radio-tracers and β⁻ probes and discuss the advantage of this method with respect to the previously explored ones: the electron low penetration power allows for simple and versatile probes and could extend RGS to tumours for which background originating from nearby healthy tissue makes probes less effective. We developed a β⁻ probe prototype and studied its performances on phantoms. By means of a detailed simulation we have also extrapolated the results to estimate the performances in a realistic case of meningioma, pathology which is going to be our first in-vivo test case. A good sensitivity to residuals down to 0.1 ml can be reached within 1 s with an administered activity smaller than those for PET-scans thus making the radiation exposure to medical personnel negligible.

New constraint on the existence of the μ+ → e+ γ decay

The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay μ(+) → e(+)γ is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.

Charged particle's flux measurement from PMMA irradiated by 80 MeV/u carbon ion beam

Hadrontherapy is an emerging technique in cancer therapy that uses beams of charged particles. To meet the improved capability of hadrontherapy in matching the dose release with the cancer position, new dose-monitoring techniques need to be developed and introduced into clinical use. The measurement of the fluxes of the secondary particles produced by the hadron beam is of fundamental importance in the design of any dose-monitoring device and is eagerly needed to tune Monte Carlo simulations. We report the measurements carried out with charged secondary particles produced from the interaction of a 80 MeV/u fully stripped carbon ion beam at the INFN Laboratori Nazionali del Sud, Catania, with a poly-methyl methacrylate target. Charged secondary particles, produced at 90° with respect to the beam axis, have been tracked with a drift chamber, while their energy and time of flight have been measured by means of a LYSO scintillator. Secondary protons have been identified exploiting the energy and time-of-flight information, and their emission region has been reconstructed backtracking from the drift chamber to the target. Moreover, a position scan of the target indicates that the reconstructed emission region follows the movement of the expected Bragg peak position. Exploiting the reconstruction of the emission region, an accuracy on the Bragg peak determination in the submillimeter range has been obtained. The measured differential production rate for protons produced with E(Prod)(kin) > 83 MeV and emitted at 90° with respect to the beam line is dN(P)/(dN(C)dΩ) (E(Prod)(kin) > 83 MeV, θ = 90°) = (2.69 ± 0.08(stat) ± 0.12(sys)) × 10⁻⁴ sr⁻¹.

New limit on the lepton-flavor-violating decay μ+→e+γ

We present a new result based on an analysis of the data collected by the MEG detector at the Paul Scherrer Institut in 2009 and 2010, in search of the lepton-flavor-violating decay μ(+)e(+)γ. The likelihood analysis of the combined data sample, which corresponds to a total of 1.8×10(14) muon decays, gives a 90% C.L. upper limit of 2.4×10(-12) on the branching ratio of the μ(+)→e(+)γ decay, constituting the most stringent limit on the existence of this decay to date.

Measurements of charged current lepton universality and |Vus| using tau lepton decays to e- ν(e) ν(τ), μ- ν(μ) ν(τ), π- ν(τ), and K- ν(τ)

Using 467  fb(-1) of e+e- annihilation data collected with the BABAR detector, we measure (B(τ- → μ- ν(μ) ν(τ)))/(B(τ- → e- ν(e) ν(τ))) =(0.9796±0.0016±0.0036), (B(τ- → π- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.5945±0.0014±0.0061), and (B(τ- → K- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.03882±0.00032±0.00057), where the uncertainties are statistical and systematic, respectively. From these precision τ measurements, we test the standard model assumption of μ-e and τ-μ charge current lepton universality and provide determinations of |Vus| experimentally independent of the decay of a kaon.

Searches for Lepton flavor violation in the decays tau{+/-}-->e{+/-}gamma and tau{+/-}-->mu{+/-}gamma

Searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon have been performed with the entire data set of (963+/-7)x10{6} tau decays collected by the BABAR detector near the Upsilon(4S), Upsilon(3S) and Upsilon(2S) resonances. The searches yield no evidence of signals and we set upper limits on the branching fractions of B(tau{+/-}-->e{+/-}gamma)<3.3x10{-8} and B(tau{+/-}-->mu{+/-}gamma)<4.4x10{-8} at 90% confidence level.

Measurement of |V(cb)| and the form-factor slope in B --> Dl- nu(l) decays in events tagged by a fully reconstructed B meson

We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V(cb)| and the form-factor slope rho2 in B --> Dl- nu(l) decays based on 460x10(6) BB events recorded at the Upsilon(4S) resonance with the BABAR detector. B --> Dl- nu(l) decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We measure B(B- --> D0 l- nu(l))/B(B- --> Xl- nu(l)) = (0.255+/-0.009+/-0.009) and B(B0 --> D+ l- nu(l))/B(B0 --> Xl- nu(l)) = (0.230+/-0.011+/-0.011), along with the differential decay distribution in B --> Dl- nu(l) decays. We then determine G(1)|V(cb)| = (42.3+/-1.9+/-1.4)x10(-3) and rho2 = 1.20+/-0.09+/-0.04, where G(1) is the hadronic form factor at the point of zero recoil.

Search for invisible decays of the Upsilon(1S)

We search for invisible decays of the Upsilon(1S) meson using a sample of 91.4 x 10(6) Upsilon(3S) mesons collected at the BABAR/PEP-II B factory. We select events containing the decay Upsilon(3S) --> pi(+)pi(-)Upsilon(1S) and search for evidence of an undetectable Upsilon(1S) decay recoiling against the dipion system. We set an upper limit on the branching fraction B(Upsilon(1S) --> invisible) < 3.0 x 10(-4) at the 90% confidence level.

Precise measurement of the e+e- --> pi+pi-(gamma) cross section with the initial state radiation method at BABAR

A precise measurement of the cross section of the process e(+)e(-) --> pi(+)pi(-)(gamma) from threshold to an energy of 3 GeV is obtained with the initial state radiation (ISR) method using 232 fb(-1) of data collected with the BABAR detector at e(+)e(-) center-of-mass energies near 10.6 GeV. The ISR luminosity is determined from a study of the leptonic process e(+)e(-) --> mu(+)mu(-)gamma(gamma). The leading-order hadronic contribution to the muon magnetic anomaly calculated using the pipi cross section measured from threshold to 1.8 GeV is (514.1 +/- 2.2(stat) +/- 3.1(syst)) x 10(-10).

Measurement of B-->K{*}(892)gamma branching fractions and CP and Isospin asymmetries

We present an analysis of the decays B{0}-->K{*0}(892)gamma and B{+}-->K{*+}(892)gamma using a sample of about 383 x 10{6} BB[-over ] events collected with the BABAR detector at the PEP-II asymmetric energy B factory. We measure the branching fractions B(B{0}-->K{*0}gamma)=(4.47+/-0.10+/-0.16) x 10{-5} and B(B{+}-->K{*+}gamma)=(4.22+/-0.14+/-0.16) x 10{-5}. We constrain the direct CP asymmetry to be -0.033<A(B-->K{*}gamma)<0.028 and the isospin asymmetry to be 0.017<Delta{0-} < 0.116, where the limits are determined by the 90% confidence interval and include both the statistical and systematic uncertainties.

Measurement of D{0}-D[-over]{0} mixing from a time-dependent amplitude analysis of D{0}-->K+pi{-}pi{0} decays

We present evidence of D{0}-D[-over ]{0} mixing using a time-dependent amplitude analysis of the decay D{0}-->K+pi{-}pi;{0} in a data sample of 384 fb{-1} collected with the BABAR detector at the PEP-II e+e{-} collider at the Stanford Linear Accelerator Center. Assuming CP conservation, we measure the mixing parameters x{Kpipi{0}}{'}=[2.61{-0.68}{+0.57}(stat)+/-0.39(syst)]%, y{Kpipi;{0}}{'}=[-0.06{-0.64}{+0.55}(stat)+/-0.34(syst)]%. This result is inconsistent with the no-mixing hypothesis with a significance of 3.2 standard deviations. We find no evidence of CP violation in mixing.

Search for a low-mass higgs boson in Upsilon(3S)-->gammaA(0), A(0)-->tau(+)tau(-) at BABAR

We search for a light Higgs boson A0 in the radiative decay Upsilon(3S)-->gammaA(0), A(0)-->tau+tau-, tau+-->e+nu(e)nu(tau), or tau+-->mu+nu(mu)nu(tau). The data sample contains 122x10(6) Upsilon(3S) events recorded with the BABAR detector. We find no evidence for a narrow structure in the studied tau+tau- invariant mass region of 4.03<m(tau+tau-)<10.10 GeV/c2. We exclude at the 90% confidence level (C.L.) a low-mass Higgs boson decaying to tau+tau- with a product branching fraction B(Upsilon(3S)-->gammaA(0))xB(A(0)-->tau+tau-)>(1.5-16)x10(-5) across the m(tau+tau-) range. We also set a 90% C.L. upper limit on the tau+tau- decay of the eta(b) at B(eta(b)-->tau+tau-)<8%.

Evidence for the eta(b)(1S) meson in radiative Upsilon(2S) decay

We have performed a search for the eta_{b}(1S) meson in the radiative decay of the Upsilon(2S) resonance using a sample of 91.6x10(6) Upsilon(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at Egamma=609.3(-4.5)(+4.6)(stat)+/-1.9(syst) MeV, corresponding to an eta(b)(1S) mass of 9394.2(-4.9)(+4.8)(stat)+/-2.0(syst) MeV/c2. The branching fraction for the decay Upsilon(2S)-->gamma(eta)b(1S) is determined to be [3.9+/-1.1(stat)-0.9+1.1(syst)]x10(-4). We find the ratio of branching fractions B[Upsilon(2S)-->gamma(eta)b(1S)]/B[Upsilon(3S)-->gamma(eta)b(1S)]=0.82+/-0.24(stat)(-0.19)(+0.20)(syst).

Search for dimuon decays of a light scalar boson in radiative transitions Upsilon-->gammaA0

We search for evidence of a light scalar boson in the radiative decays of the Upsilon(2S) and Upsilon(3S) resonances: Upsilon(2S,3S)-->gammaA0, A0-->mu+mu-. Such a particle appears in extensions of the standard model, where a light CP-odd Higgs boson naturally couples strongly to b quarks. We find no evidence for such processes in the mass range 0.212 < or = mA0 < or = 9.3 GeV in the samples of 99 x 10(6) Upsilon(2S) and 122 x 10(6) Upsilon(3S) decays collected by the BABAR detector at the SLAC PEP-II B factory and set stringent upper limits on the effective coupling of the b quark to the A0. We also limit the dimuon branching fraction of the etab meson: B(etab-->mu+mu-)<0.9% at 90% confidence level.

Measurement of semileptonic B decays into orbitally excited charmed mesons

We present a study of B decays into semileptonic final states containing charged and neutral D1(2420) and D_{2};{*}(2460). The analysis is based on a data sample of 208 fb;{-1} collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. With a simultaneous fit to four different decay chains, the semileptonic branching fractions are extracted from measurements of the mass difference Deltam=m(D;{**})-m(D) distributions. Product branching fractions are determined to be B(B;{+}-->D_{1};{0}l;{+}nu_{l})xB(D_{1};{0}-->D;{*+}pi;{-})=(2.97+/-0.17+/-0.17)x10;{-3}, B(B;{+}-->D_{2};{*0}l;{+}nu_{l})xB(D_{2};{*0}-->D;{(*)+}pi;{-})=(2.29+/-0.23+/-0.21)x10;{-3}, B(B;{0}-->D_{1};{-}l;{+}nu_{l})xB(D_{1};{-}-->D;{*0}pi;{-})=(2.78+/-0.24+/-0.25)x10;{-3} and B(B;{0}-->D_{2};{*-}l;{+}nu_{l})xB(D_{2};{*-}-->D;{(*)0}pi;{-})=(1.77+/-0.26+/-0.11)x10;{-3}. In addition we measure the branching ratio Gamma(D_{2};{*}-->Dpi;{-})/Gamma(D_{2};{*}-->D;{(*)}pi;{-})=0.62+/-0.03+/-0.02.

Search for second-class currents in tau;{-} --> omegapi;{-}nu_{tau}

We report an analysis of tau;{-} decaying into omegapi;{-}nu_{tau} with omega --> pi;{+}pi;{-}pi;{0} using a data sample containing nearly 320 x 10;{6}tau pairs collected with the BABAR detector at the PEP-II B-Factory. We find no evidence for second-class currents, and we set an upper limit of 0.69% at 90% confidence level for the fraction of second-class currents in this decay mode.

Improved limits on lepton-flavor-violating tau decays to lphi, lrho, lK, and lK

We search for the neutrinoless, lepton-flavor-violating tau decays tau- -->l-}V0, where l is an electron or muon and V0 is a vector meson reconstructed as phi-->K+K-, rho-->pi+pi-, K-->K+pi-, K[over ]-->K-pi+. The analysis has been performed using 451 fb-1 of data collected at an e+e- center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage rings. The number of events found in the data is compatible with the background expectation, and upper limits on the branching fractions are set in the range (2.6-19)x10-8 at the 90% confidence level.

Measurement of B-->Xgamma decays and determination of |Vtd/Vts|

Using a sample of 383 x 10;{6} BB[over ] events collected by the BABAR experiment, we measure sums of seven exclusive final states B-->X_{d(s)}gamma, where X_{d}(X_{s}) is a nonstrange (strange) charmless hadronic system in the mass range 0.6-1.8 GeV/c;{2}. After correcting for unmeasured decay modes in this mass range, we obtain a branching fraction for b-->dgamma of (7.2+/-2.7(stat)+/-2.3(syst))x10;{-6}. Taking the ratio of X_{d} to X_{s} we find Gamma(b-->dgamma)/Gamma(b-->sgamma)=0.033+/-0.013(stat)+/-0.009(syst), from which we determine |V_{td}/V_{ts}|=0.177+/-0.043.

Improved measurement of B+ --> rho+ rho0 and determination of the quark-mixing phase angle alpha

We present improved measurements of the branching fraction B, the longitudinal polarization fraction f{L}, and the direct CP asymmetry A{CP} in the B meson decay channel B;{+}-->rho;{+}rho;{0}. The data sample was collected with the BABAR detector at SLAC. The results are B(B;{+}-->rho;{+}rho;{0})=(23.7+/-1.4+/-1.4) x 10;{-6}, f{L}=0.950+/-0.015+/-0.006, and A{CP}=-0.054+/-0.055+/-0.010, where the uncertainties are statistical and systematic, respectively. Based on these results, we perform an isospin analysis and determine the Cabibbo-Kobayashi-Maskawa phase angle alpha=arg(-V{td}V{tb};/V{ud}V{ub}) to be (92.4{-6.5};{+6.0}) degrees.

Evidence for X(3872)-->psi(2S)gamma in B(+/-)-->X(3872)K(+/-) decays and a study of B-->cc[over ]gammaK

In a search for B-->cc[over ]gammaK decays with the BABAR detector, where cc[over ] includes J/psi and psi(2S), and K includes K(+/-), K(S)(0), and K(*)(892), we find evidence for X(3872)-->J/psigamma and X(3872)-->psi(2S)gamma with 3.6sigma and 3.5sigma significance, respectively. We measure the product of branching fractions B(B(+/-)-->X(3872)K(+/-))xB(X(3872)-->J/psigamma)=[2.8+/-0.8(stat)+/-0.1(syst)]x10(-6) and B(B(+/-)-->X(3872)K(+/-))xB(X(3872)-->psi(2S)gamma)=[9.5+/-2.7(stat)+/-0.6(syst)]x10(-6).

Direct CP, lepton flavor, and isospin asymmetries in the decays B-->K(*)l+l-

We measure branching fractions and integrated rate asymmetries for the rare decays B-->K(*)l+l-, where l+l- is either e+e- or micro+micro-, using a sample of 384x10(6) BB events collected with the BABAR detector at the PEP-II e+e- collider. We find no evidence for direct CP or lepton-flavor asymmetries. However, for dilepton masses below the J/psi resonance, we find evidence for unexpectedly large isospin asymmetries in both B-->Kl+l- and B-->K*l+l- which differ, respectively, by 3.2sigma and 2.7sigma, including systematic uncertainties, from the standard model expectations.

Measurement of the e;{+}e;{-}-->bb[over ] Cross Section between sqrt[s]=10.54 and 11.20 GeV

We report e;{+}e;{-}-->bb[over ] cross section measurements by the BABAR experiment performed during an energy scan in the range of 10.54 to 11.20 GeV at the SLAC PEP-II e;{+}e;{-} collider. A total relative error of about 5% is reached in more than 300 center-of-mass energy steps, separated by about 5 MeV. These measurements can be used to derive precise information on the parameters of the Upsilon(10860) and Upsilon(11020) resonances. In particular we show that their widths may be smaller than previously measured.

Measurement of the branching fractions of B-->D**(l) nu(l) decays in events tagged by a fully reconstructed B meson

We report a measurement of the branching fractions of B-->D**(l) nu(l), decays based on 417 fb(-1) of data collected at the Y(4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. Events are selected by full reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m(D(*) pi)- m(D(*)) is performed to extract the signal yields of the different D** states. We observe the B-->D**l(-1)nu(l) decay modes corresponding to the four D states predicted by heavy quark symmetry with a significance greater than 5 standard deviations including systematic uncertainties.

Searches for B meson decays to phiphi, phirho, phif_{0}(980), and f_{0}(980)f_{0}(980) final states

We present the results of searches for B decays to charmless final states involving varphi, f_{0}(980), and charged or neutral rho mesons. The data sample corresponds to 384x10;{6} BB[over ] pairs collected with the BABAR detector operating at the PEP-II asymmetric-energy e;{+}e;{-} collider at SLAC. We find no significant signals and determine the following 90% confidence level upper limits on the branching fractions, including systematic uncertainties: B(B;{0}-->varphivarphi)<2.0x10;{-7}, B(B;{+}-->varphirho;{+})<30x10;{-7}, B(B;{0}-->varphirho;{0})<3.3x10;{-7}, B[B;{0}-->varphif_{0}(980)]xB[f_{0}(980)-->pi;{+}pi;{-}]<3.8x10;{-7}, and B[B;{0}-->f_{0}(980)f_{0}(980)]xB[f_{0}(980)-->pi;{+}pi;{-}]xB[f_{0}(980)-->K;{+}K;{-}]<2.3x10;{-7}.

Measurement of the CP asymmetry in b-->sgamma using a sum of exclusive final states

We perform a measurement of the CP asymmetry in b-->sgamma decays using a sample of 383 x 10(6) B[over] B events collected by the BABAR detector at the SLAC PEP-II asymmetric B factory. We reconstruct 16 flavor-specific B decay modes containing a high-energy photon and a hadronic system X_(s) containing an s quark. We measure the CP asymmetry to be -0.011+/-0.030(stat)+/-0.014(syst) for a hadronic system mass between 0.6 and 2.8 GeV/c(2).

Observation and polarization measurements of B+/- -->phiK1 +/- and B +/- -->phiK2 *+/-

With the full BABAR data sample of 465 x 10(6) B(over)B pairs, we observe the decays B+/- -->phiK_(1)(1270) +/- and B +/- -->phiK*_(2)(1430)+/-. We measure the branching fractions (6.1+/-1.6+/-1.1) x 10(-6) and (8.4+/-1.8+/-1.0) x 10(-6) and the fractions of longitudinal polarization 0.46 (+0.12+0.06) _(-0.13-0.07) and 0.80(+0.09)_(-0.10)+/-0.03, respectively. We also report on the B+/- -->phiK*_(0)(1430)+/- decay branching fraction of (7.0+/-1.3+/-0.9) x 10(-6) and several parameters sensitive to CP violation and interference in the above three decays. Upper limits are placed on the B+/- decay rates to final states with phi and K_1(1400)+/-, K*(1410)+/-, K2(1770)+/-, or K_2(1820)+/-. Understanding the observed polarization pattern requires amplitude contributions from an uncertain source.

Study of B meson decays with excited eta and eta' mesons

Using 383 x 10(6) BBover pairs from the BABAR data sample, we report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to KKover* or etapipi final states with mass in the range (1.2-1.8) GeV/c2. We observe a significant enhancement at the low KKover* invariant mass which is interpreted as B+-->eta(1475)K+, find evidence for the decay B+-->eta(1295)K+, and place upper limits on the decays B+-->eta(1405)K+, B+-->f1(1285)K+, B+-->f1(1420)K+, and B+-->phi(1680)K+.

Observation of Y(3940) --> J/psiomega in B --> J/psiomegaK at BABAR

We present a study of the decays B;{0,+}-->J/psiomegaK;{0,+} using 383x10;{6} BB[over ] events obtained with the BABAR detector at PEP-II. We observe Y(3940)-->J/psiomega, with mass 3914.6_{-3.4};{+3.8}(stat)+/-2.0(syst) MeV/c;{2}, and width 34_{-8};{+12}(stat)+/-5(syst) MeV. The ratio of B0 and B+ decay to YK is 0.27_{-0.23};{+0.28}(stat)-0.01+0.04(syst), and the relevant B0 and B+ branching fractions are reported.