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We report on event structure and double helicity asymmetry ($A_LL$) of jetproduction in longitudinally polarized p+p collisions at $\sqrt{s}$=200 GeV.Photons and charged particles were measured at midrapidity $|\eta| < 0.35$ withthe requirement of a high-momentum ($>2$ GeV/$c$) photon in each event.Measured event structure is compared with {\sc pythia} and {\sc geant}simulations. The shape of jets and the underlying event were well reproduced atthis collision energy. For the measurement of jet $A_{LL}$, photons and chargedparticles were clustered with a seed-cone algorithm to obtain the cluster $p_T$sum ($p_T^{\rm reco}$). The effect of detector response and the underlyingevents on $p_T^{\rm reco}$ was evaluated with the simulation. The productionrate of reconstructed jets is satisfactorily reproduced with the NLO pQCD jetproduction cross section. For $4 < p_T^{\rm reco} < 12$ GeV/$c$ with an averagebeam polarization of $< P > = 49%$ we measured $A_{LL} = -0.0014 \pm0.0037^{\rm stat}$ at the lowest $p_T^{\rm reco}$ bin (4-5 GeV/$c$) and$-0.0181 \pm 0.0282^{\rm stat}$ at the highest $p_T^{\rm reco}$ bin (10-12GeV/$c$) with a beam polarization scale error of 9.4% and a $\pT$ scale errorof 10%. Jets in the measured $p_T^{\rm reco}$ range arise primarily fromhard-scattered gluons with momentum fraction $0.02 < x < 0.3$ according to {\scpythia}. The measured $A_{LL}$ is compared with predictions that assume various$\Delta G(x)$ distributions based on the GRSV parameterization. The presentresult imposes the limit $-1.1 < \int_{0.02}^{0.3}dx \Delta G(x, \mu^2 = 1 {\rmGeV}^2) < 0.4$ at 95% confidence level or $\int_{0.02}^{0.3}dx \Delta G(x,\mu^2 = 1 {\rm GeV}^2) < 0.5$ at 99% confidence level.

Event Structure and Double Helicity Asymmetry in Jet Production from Polarized p+p Collisions at sqrt(s) = 200 GeV