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Jonathan L. Rosner

Publications and source records attributed to Jonathan L. Rosner.

At least 73 records · Page 4Linked to original sources
arXiv2013

Hadronic and radiative $D^*$ decays

A recent measurement of the total $D^{*+}$ width, $Γ_{\rm tot}(D^{*+}) = (83.3 \pm 1.3 \pm 1.4)$ keV, is shown to be close to earlier predictions based on the single-quark-transition hypothesis. Those predictions are updated using more recent masses and branching fractions to a value of 80.4 keV, with a small uncertainty associated with the radiative branching fractions of $D^{*0}$ and $D^{*+}$. A prediction for the total width of $D_2(2460)$ and its partial width into $D^* π$ and $D π$ is also updated, and found to be in agreement with experiment.

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arXiv2013

Shift in weak phase $γ$ due to CP asymmetries in $D$ decays to two pseudoscalar mesons

A difference of several tenths of a percent has been observed between the direct CP asymmetries of $D^0\to K^+K^-$ and $D^0\to π^+π^-$. It has been noted recently that CP asymmetries in such singly-Cabibbo-suppressed (SCS) decays can affect the determination of the weak phase $γ$ using the Gronau-London-Wyler method of comparing rates for $B^+ \to D K^+$ and $B^- \to D K^-$, where $D$ is a superposition of $D^0$ and $\od$ decaying to a CP eigenstate. Using an analysis of the CP asymmetries in SCS decays based on a $c \to u$ penguin amplitude with standard model weak phase but enhanced by CP-conserving strong interactions, we estimate typical shifts in $γ$ of several degrees and pinpoint measurements which would reduce uncertainties to an acceptable level.

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arXiv2012

Recent Results in Bottomonium

Great strides have been made in the understanding of bound states of a bottom quark $b$ and its antiquark $\bar b$ since the discovery of the first $Υ$ resonances in 1977. These {\it bottomonium} bound states have a rich spectrum whose masses and transition amplitudes shed valuable light on the strong interactions. The present article reviews some recent developments in bottomonium physics. These include the discovery of the spin-singlet states $η_b$ and $h_b$, the first D-wave states, one or more candidates for spin-triplet $χ_b(3P)$ excitations, and above-threshold states with strong transitions to states below threshold. Information on transitions, production, and signatures of new physics is also presented.

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arXiv2012

Rescattering Contributions to rare B-Meson Decays

Several $B$ and $B_s$ decays have been observed which have been cited as evidence for exchange ($E$), penguin annihilation ($PA$) and annihilation ($A$) processes, such as $\bar b d \to \bar u u$, $\bar b s \to \bar u u$ and $\bar b u \to W^* \to \bar c s$, respectively. These amplitudes are normally thought to be suppressed, as they involve the spectator quark in the weak interaction and thus should be proportional to the $B$-meson decay constant $f_B$. However, as pointed out a number of years ago, they can also be generated by rescattering from processes whose amplitudes do not involve $f_B$, such as color-favored tree amplitudes. In this paper we investigate a number of processes such as $B^0 \to K^+ K^-$, $B_s \to π^+ π^-$, and $B^+ \to D_s^+ ϕ$, and identify promising states from which they can be generated by rescattering. We find that $E$ and $PA$-type processes are characterized respectively by amplitudes ranging from 5% to 10% and from 15% to 20% with respect to the largest amplitude from which they can rescatter. Based on this regularity, using approximate flavor SU(3) symmetry in some cases and time-reversal invariance in others, we predict the branching fractions for a large number of as-yet-unseen $B$ and $B_s$ decays in an extensive range from order $10^{-9}$ to $10^{-4}$.

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arXiv2012

Revisiting D0-D0bar mixing using U-spin

We prove that $D^0$-$\bar D^0$ mixing in the standard model occurs only at second order in U-spin breaking. The U-spin subgroup of SU(3) is found to be a powerful tool for analyzing the cancellation of intermediate-state contributions to the $D^0$--$\od^0$ mixing parameter $y = ΔΓ/(2 Γ)$. Cancellations due to states {\it within a single U-spin triplet} are shown to be valid to first order in U-spin breaking. Illustrations are given for triplets consisting of (a) pairs of charged pions and kaons; (b) pairs of neutral pseudoscalar members of the meson octet; (c) charged vector-pseudoscalar pairs, and (d) states of four charged kaons and pions.

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arXiv2012

Nonleptonic Charm Decays and CP Violation

In this talk we briefly present a flavor-SU(3) technique to study branching ratios and direct CP asymmetries $D$-meson decays. The first part of the talk is meant to set up a foundation, based on previous work, to deal with flavor-SU(3) amplitudes and relative strong phases. In addition, we present a model for dealing with SU(3)-breaking in branching ratio measurements of SCS $D^0$ decays. In the second part of the talk we make use of a proposal for an enhanced CP-violating penguin in the SM, to explain the recent LHCb and CDF observations of CP violation in SCS $D^0$ decays. Furthermore, we use our model to predict CP violation in $π^0π^0$ and $K^+\bar{K}^0$ final states. Large experimental bounds on individual CP asymmetries give rise to a large allowed range of $δ$, the strong phase of the CP-violating penguin. We also briefly discuss future prospects.

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arXiv2012

Direct CP Violation in D Decays in view of LHCb and CDF Results

The LHCb and CDF Collaborations have recently reported evidence for a CP asymmetry around -0.7% in $ΔA_{CP}$, the difference between $A_{CP}(D^0 \to K^+ K^-)$ and $A_{CP}(D^0 \to π^+π^-)$. In the Standard Model this effect may be accounted for by enhanced $1/m_c$ corrections in a CP-violating penguin amplitude governed by a Cabibbo-Kobayashi-Maskawa (CKM) factor $V^*_{cb}V_{ub}$. A consistent scheme based on broken flavor SU(3) is presented relating Cabibbo-favored (CF) and singly-Cabibbo-suppressed (SCS) $D$ meson decay rates into two pseudoscalars. Two important ingredients supporting the above interpretation for $ΔA_{CP}$ are a large exchange amplitude in CF decays which is formally $1/m_c$-suppressed, and a pure $ΔU=0$ U-spin breaking CP-conserving penguin amplitude involving $V^*_{cs}V_{us}$ and $V^*_{cd}V_{ud}$ which accounts for the difference between the $D^0\to K^+K^-$ and $D^0\to π^+π^-$ decay rates. The magnitudes of the CP conserving and CP violating penguin amplitudes, where the former involves U-spin breaking at a level of 10%, are shown to be related to each other by the magnitudes of corresponding CKM factors. This simple scheme leads to preferable sign predictions for CP asymmetries in charmed meson decays into two pseudoscalars and to correlations between asymmetries in two pairs of these processes.

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arXiv2012

Prospects for improved $Λ_c$ branching fractions

The experimental uncertainty on the branching fraction $\b(Λ_c \to p K^- π^+) = (5.0 \pm 1.3)%$ has not decreased since 1998, despite a much larger data sample. Uncertainty in this quantity dominates that in many other quantities, including branching fractions of $Λ_c$ to other modes, branching fractions of $b$-flavored baryons, and fragmentation fractions of charmed and bottom quarks. Here we advocate a lattice QCD calculation of the form factors in $Λ_c \to Λ\ell^+ ν_\ell$ (the case $\ell = e^+$ is simpler as the mass of the lepton can be neglected). Such a calculation would yield an absolute prediction for the rate for $Λ_c \to Λ\ell^+ ν_\ell$. When combined with the $Λ_c$ lifetime, it could provide a calibration for an improved set of $Λ_c$ branching fractions as long as the accuracy exceeds about 25%.

hep-ph↗
arXiv2012

Flavor-SU(3) tests from $D^0 \to K^0 K^- π^+$ and $D^0 \to \bar K^0 K^+ π^-$ Dalitz plots

The processes $D^0\to K^0 K^-π^+$ and $D^0\to\ok K^+π^-$ involve intermediate vector resonances whose amplitudes and phases are related to each other via flavor-SU(3) symmetry. Dalitz plots for these two processes can shed light on the usefulness of this symmetry in studying charm decays. Until this year the only available data on this process came from a conference report in 2002 by the BaBar Collaboration, but now an independent data sample of higher statistics has become available from the CLEO Collaboration. The goal is to predict Dalitz plot amplitudes and phases assuming flavor-SU(3) symmetry and compare them with experiment. An SU(3) fit can account for the relative magnitudes of the amplitudes for the decays $D^0 \to K^{*-}K^+$ and $D^0 \to K^{*+}K^-$, but neither the current BaBar sample (based on an integrated luminosity of 22 fb$^{-1}$) nor the CLEO analysis has significant evidence for the decays $D^0\to K^{*0}\ok$ and $D^0 \to \oks K^0$. At this level one is unable to compare magnitudes and phases with theoretical predictions. The purpose of this Letter is to advocate an analysis using the full BaBar sample (more than 20 times the 2002 value). It should definitively determine whether predicted magnitudes and phases agree with experiment. A similar analysis should be possible with an even larger sample of events collected by the Belle Collaboration at KEK-B.

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arXiv2012

Non-factorizable effects in top quark production

The production of top-antitop pairs at the Fermilab Tevatron shows a forward-backward asymmetry in which the top quark tends to follow the proton direction, while the antitop tends to follow the antiproton direction. The effect grows with increasing effective mass $m_{t \bar t}$ of the top-antitop pair, and with increasing rapidity difference between the top and antitop. The observed effect is about three times as large as predicted by next-to-leading-order QCD, but with the same sign. An estimate of non-factorizable effects based on a QCD string picture finds they are negligible, but that small distortions of the $m_t$ spectrum are possible. Tests for such effects, both at and above the level of this estimate, are suggested.

hep-ph↗
arXiv2012

CP asymmetries in singly-Cabibbo-suppressed $D$ decays to two pseudoscalar mesons

The LHCb Collaboration has recently reported evidence for a CP asymmetry approaching the percent level in the difference between $D^0 \to π^+ π^-$ and $D^0 \to K^+ K^-$. We analyze this effect as if it is due to a penguin amplitude with the weak phase of the standard model $c \to b \to u$ loop diagram, but with a CP-conserving enhancement as if due to the strong interactions. In such a case the magnitude and strong phase of this amplitude $P_b$ are correlated in order to fit the observed CP asymmetry, and one may predict CP asymmetries for a number of other singly-Cabibbo-suppressed decays of charmed mesons to a pair of pseudoscalar mesons. Non-zero CP asymmetries are expected for $D^+ \to K^+ \ok$ (the most promising channel for which a non-zero CP asymmetry has not yet been reported), as well as $D^0 \to π^0 π^0$, $D_s^+ \to π^+ \ko$, and $D_s \to π^0 K^+$. No CP asymmetry is predicted for $D^+ \to π^+ π^0$ or $D^0 \to \ko \ok$ in this framework.

hep-ph↗
arXiv2012

Leptonic decays of charged pseudoscalar mesons - 2012

We review the physics of purely leptonic decays of $π^\pm$, $K^\pm$, $D^{\pm}$, $D_s^\pm$, and $B^\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The interplay between theory and experiment is different for each particle. Theoretical predictions of $f_B$ that are needed in the $B$ sector can be tested by measuring $f_{D^+}$ and $f_{D_s^+}$ in the charm sector. The lighter $π^{\pm}$ and $K^{\pm}$ mesons provide stringent comparisons between experiment and theory due to the accuracy of both the measurements and the theoretical predictions. This review was prepared for the Particle Data Group's 2012 edition.

hep-ex↗
arXiv2012

Background dependence of dimuon asymmetry in $\bar p p$ interactions at $\sqrt{s} = 1.96$ TeV

The D0 Collaboration has reported an anomalous charge asymmetry in the production of same-sign muon pairs at the Fermilab Tevatron. The magnitude of this effect depends on the subtraction of several backgrounds, the most notable of which is due to kaons being misidentified as muons either through decays in flight or punch-through. The present authors suggested a check on such backgrounds consisting of a tight restriction on the muon impact parameter $b$, to confirm that this excess was indeed due to $B_{(s)}$ meson decays. The D0 Collaboration has performed a related check applying transverse impact parameter (IP) restrictions, whose implications are discussed. We study background asymmetry predictions for events involving two muons with IP bounds which are complementary to each other. These predictions may be used in future measurements of the net charge asymmetry from $B_{(s)}$ decays.

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arXiv2011

A Leptophobic Z' And Dark Matter From Grand Unification

We explore the phenomenology of Grand Unified Models based on the E_6 group, focusing on the Z' with suppressed couplings to leptons that can appear in such models. We find that this Z' can accommodate the W+dijets anomaly reported by the CDF collaboration. Furthermore, a viable dark matter candidate in the form of a right-handed sneutrino is also present within the fundamental 27-dimensional representation of E_6. Through its sizable couplings to the Z', the dark matter is predicted to possess an elastic scattering cross section with neutrons which can generate the signals reported by the CoGeNT and DAMA/LIBRA collaborations. To avoid being overproduced in the early universe, the dark matter must annihilate to leptons through the exchange of charged or neutral fermions which appear in the 27 of E_6, providing an excellent fit to the gamma ray spectrum observed from the Galactic Center by the Fermi Gamma Ray Space Telescope.

hep-ph↗
arXiv2011

Relative Phases in $D^0\to K^0 K^-π^+$ AND $D^0\to\ok K^+π^-$ Dalitz Plots

The processes $D^0\to K^0 K^-π^+$ and $D^0\to\ok K^+π^-$ involve intermediate vector resonances whose amplitudes and phases are related to each other via flavor SU(3) symmetry. A closer look at Dalitz plots for these two processes is expected to shed light on our understanding of the usefulness of flavor SU(3) symmetry in studying charm decays. In the present work we use data from the BaBar Collaboration's publication in 2002. The goal is to reproduce Dalitz plot amplitudes and phases assuming flavor SU(3) symmetry and compare them with experiment. While an SU(3) fit is able to account for the relative magnitudes of the amplitudes for the decays $D^0 \to K^{*-}K^+$ and $D^0 \to K^{*+}K^-$, the current BaBar sample (based on an integrated luminosity of only 22 fb$^{-1}$) provides only 1--$2 σ$ evidence for the decays $D^0\to K^{*0}\ok$ and $D^0 \to \oks K^0$, with magnitudes and phases not in accord with predictions. The CLEO collaboration could potentially produce an analysis using data with better statistics, and an analysis based on the full BaBar sample (more than 20 times the 2002 value) should definitively settle the question.

hep-ph↗
arXiv2011

Triple product asymmetries in K, D_(s) and B_(s) decays

One distinguishes between "true" CP violating triple product (TP) asymmetries which require no strong phases and "fake" asymmetries which are due to strong phases but require no CP violation. So far a single true TP asymmetry has been measured in $K_L\to π^+π^- e^+e^-$. A general discussion is presented for T-odd TP asymmetries in four-body decays. It is shown that TP asymmetries vanish for two identical and kinematically indistinguishable particles in the final state. Two examples are $D^0\to K^-π^+π^-π^+$ and $D^+\to K^-π^+π^+π^0$. A non-zero TP asymmetry can be expected when non-trivial kinematic correlations exist, as in the decay $K_L \to e^+ e^- e^+ e^-$. Triple product asymmetries measured in charmed particle decays indicate an interesting pattern of final-state interactions. We reiterate a discussion of TP asymmetries in $B$ meson decays to two vector mesons each decaying to a pseudoscalar pair, extending results to decays where one vector meson decays into a lepton pair. We derive expressions for time-dependent TP asymmetries for neutral B decays to flavorless states in terms of the neutral $B$ mass difference $Δm$ and the width-difference $ΔΓ$. Time-integrated true CP violating asymmetries, measurable for untagged $B_s$ decays, are shown to be suppressed by neither $Γ_s/Δm_s$ nor $ΔΓ_s/Γ_s$ if transversity amplitudes for CP-even and CP-odd states involve different weak phases. In contrast, fake asymmetries require flavor tagging and are suppressed by the former ratio when time-integrated. We apply our results to $B\to K^*ϕ$ and $B_s\toϕϕ$ data and suggest an application for $B_s\to J/ψϕ$.

hep-ph↗
arXiv2011

Charm at Threshold

Results from the CLEO Collaboration, mainly dealing with the study of charmed mesons produced at flavor threshold but also covering other areas of CLEO's investigation, are reviewed.

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