Search for very light CP-odd Higgs Boson in radiative decays of Upsilon(1S)

We search for a non-SM-like CP-odd Higgs boson (a(1)(0)) decaying to tau(+)tau(-) or mu(+)mu(-) in radiative decays of the Upsilon(1S). No significant signal is found, and upper limits on the product branching ratios are set. Our tau(+)tau(-) results are almost 2 orders of magnitude more stringent than previous upper limits. Our data provide no evidence for a Higgs state with a mass of 214 MeV decaying to mu(+)mu(-), previously proposed as an explanation for 3 Sigma(+)-->pmu(+)mu(-) events observed by the HyperCP experiment. Our results constrain NMSSM models.     

Observation of chicJ radiative decays to light vector mesons

Using a total of 2.74 x 10(7) decays of the psi(2S) collected with the CLEO-c detector, we present a study of chi(cJ)-->gammaV, where V=rho(0), omega, phi. The transitions chi(c1)-->gammarho(0 and chi(c1)-->gammaomega are observed with B(chi(c1)-->gammarho(0))=(2.43+/-0.19+/-0.22) x 10(-4) and B(chi(c1)-->gammaomega)=(8.3+/-1.5+/-1.2) x 10(-5). In the chi(c1)-->gammarho(0) transition, the final state meson is dominantly longitudinally polarized. Upper limits on the branching fractions of other chi(cJ) states to light vector mesons are presented.     

Hidden Higgs particles

In a class of extended Higgs structures containing a light or massless pseudoscalar it is quite likely the normal Wienberg-Salam Higgs particle decays preferentially into spin-zero bosons if its mass is below the t$\text{t}$ threshold. These spin-zero bosons may be invisible either because they do not decay or because they decay into neutrinos. Thus Higgs particles may be light enough to be produced at accessible energies but difficult to detect through their decay products.     

Reactions of furocoumarins. II. Synthetic aminomethyl psoralens via chloromethylation or benzylic bromination

Several psoralen derivatives have been synthesized in order to evaluate their efficacy as photochemotherapeutic (PUVA) agents, including a variety of 4′-substituted-4,5′,8-trimethypsoralen compounds ( 1d-j ). Improved synthesis of the very potent photosensitizers 8-methylpsoralen ( 6a ) and 4,8-dimethylpsoralen ( 6b ) are described and 6a has been shown to undergo formylation in the 4′-position. Free radical bromination of 6a and 6b with NBS affords primarily 8-bromomethyl derivatives ( 8a and d ), which are readily converted into the 8-aminomethyl derivatives ( 8c and f ) by the Gabriel method. If the 4′-position is blocked, electrophilic substitution apparently occurs primarily in the 5′-position of the psoralen system. At least, chloromethylation of 4′-methylpsoralen ( 9 ) affords mainly 5′-chloromethyl derivatives ( 10a and d ), which also lead to aminomethylpsoralens ( 10c and f ).     

A Cl nuclear quadrupole resonance study of NH4ICl4·H2O

The “missing” fourth ³⁵Cl NQR frequency postulated for NH₄ICl₄H₂O at room temperature has been observed. Four signals were also found for this compound at 195K, but the results at 77K were less clear-cut, with either five or (probably) six resonances detected. The occurrence of a phase transition between 77 and 195K seems likely. A structure is suggested for the ICl₄⁻ ion at room temperature from the relationship found previously between NQR frequency and bond length in tetrachloroiodates.     

Order by Disorder,without Order,in a Two-Dimensional Spin System with O(2) Symmetry

We present a rigorous proof of an ordering transition for a two-component two-dimensional antiferromagnet with nearest and next-nearest neighbor interactions. The low-temperature phase contains two states distinguished by local order among columns or, respectively, rows. Overall, there is no magnetic order in accord with the classic Mermin-Wagner theorem. The method of proof employs a rigorous version of order by disorder, whereby a high degeneracy among the ground states is lifted according to the differences in their associated spin-wave spectra.Communicated by Jennifer Chayessubmitted 07/10/03, accepted 28/04/04     

The synthesis and fluorescent properties of analogues of the zinc(II) specific fluorophore zinquin ester

The synthesis and fluorescent properties in the absence and presence of zinc(II) of a range of 2-substituted derivatives of N-(6-methoxy-2-methyl-8-quinolyl)-4-methylbenzenesulfonamide are described. These analogues formed complexes with zinc(II) as indicated by a bathochromic shift in their UV/vis spectra. Analogues with isobutenyl and isobutyl side chains at the 2-position formed fluorescent complexes whose fluorescence was stronger than that of the 2-methyl-containing parent. These derivatives were converted, via conversion to the phenol with boron tribromide and reaction with ethyl bromoacetate, to systems with ester-containing side chains analogous to zinquin ester, a specific cellular fluorophore for zinc(II). All of these ester derivatives formed complexes with zinc(II) resulting in a bathochomic shift in their UV/vis spectra. Compounds with isobutyl, isobutenyl, and styryl side chains exhibited increased fluorescence compared to that of zinquin ester in the presence of zinc(II). The compound with the 2-isobutyl side chain was more selective in its fluorescence for zinc(II) over cadmium(II) compared to zinquin ester.     

Measurement of the decay constant f(Ds+) using D(s+)-->l+ nu

We measure the decay constant f(Ds+) using the D(s+)-->l+ nu channel, where the l+ designates either a mu+ or a tau+, when the tau+ -->pi+ nu. Using both measurements we find f(Ds+)=274+/-13+/-7 MeV. Combining with our previous determination of f(D+), we compute the ratio f(Ds+)/f(D+)=1.23+/-0.11+/-0.04. We compare with theoretical estimates.