The cross section of the process e(+) e(-) -> eta ' J/ psi is measured at center-of-mass (c.m.) energies from root S = 4.178 to 4.600 GeV using data samples corresponding to a total integrated luminosity of 11 fb(-1) collected with the BESIII detector operating at the BEPCII storage ring. The dependence of the cross section on root S shows an enhancement around 4.2 GeV. While the shape of the cross section cannot be fully explained with a single psi(4160) or psi(4260) state, a coherent sum of the two states does provide a reasonable description of the data.

There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESIII and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESIII, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESIII during the remaining operation period of BEPCII. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCII to higher luminosity.

The SU(3)-flavor violating decay J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c. is studied using (1310.6 +/- 7.0) x 10(6) J/psi events collected with the BESIII detector at BEPCII, and the branching fraction is measured to be B(J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c.) = (3.17 +/- 0.02(stat) +/- 0.08(syst)) x 10(-4). This result is consistent with previous measurements with an order of magnitude improved precision. The angular parameter for this decay is measured for the first time and is found to be alpha = -0.21 +/- 0.04(stat) +/- 0.06(syst). In addition, we report evidence for the radiative decay Xi(1530)(-) -> gamma Xi(-) with a significance of 3.9 sigma, including the systematic uncertainties. The 90% confidence level upper limit on the branching fraction is determined to be B(Xi(1530)(-) -> gamma Xi(-)) <= 3.7%.

The process of e(+)e(-) -> p (p) over bar is studied at 22 center-of-mass energy points (root s) from 2.00 to 3.08 GeV, exploiting 688.5 pb(-1) of data collected with the BESIII detector operating at the BEPCII collider. The Born cross section (sigma(p (p) over bar)) of e(+)e(-) -> p (p) over bar is measured with the energy-scan technique and it is found to be consistent with previously published data, but with much improved accuracy. In addition, the electro-magnetic form-factor ratio (vertical bar G(E)/G(M)vertical bar) and the value of the effective (vertical bar G(eff)vertical bar), electric (vertical bar G(E)vertical bar), and magnetic (vertical bar G(M)vertical bar) form factors are measured by studying the helicity angle of the proton at 16 center-of-mass energy points. vertical bar G(E)/G(M)vertical bar and vertical bar G(M)vertical bar are determined with high accuracy, providing uncertainties comparable to data in the spacelike region, and vertical bar G(E)vertical bar is measured for the first time. We reach unprecedented accuracy, and precision results in the timelike region provide information to improve our understanding of the proton inner structure and to test theoretical models which depend on nonperturbative quantum chromodynamics.

Using a total of 11.0 fb(-1) of e(+)e(-) collision data with center-of-mass energies between 4.009 and 4.6 GeV and collected with the BESIII detector at BEPCII, we measure fifteen exclusive cross sections and effective form factors for the process e(+)e(-) -> Xi(-)Xi(+) by means of a single baryon-tag method. After performing a fit to the dressed cross section of e(+)e(-)-> Xi(-)Xi(+) no significant psi(4230) or psi(4260) resonance is observed in the Xi(-)Xi(+) final states, and upper limits at the 90% confidence level on T B-ee for the processes psi(4230)psi/(4260) -> Xi(-)Xi(+) are determined. In addition, an excited Xi baryon at 1820 MeV/c(2) is observed with a statistical significance of 6.2-6.5 sigma by including the systematic uncertainty, and the mass and width are measured to be M = (1825.5 +/- 4.7 +/- 4.7) MeV/c(2) and Gamma = (17.0 +/- 15.0 +/- 7.9) MeV, which confirms the existence of the J(P) =3-/2 state Xi (1820).

A partial-wave analysis is performed for the process e(+)e(-) -> K+ K- pi(0)pi(0) at the center-of-mass energies ranging from 2.000 to 2.644 GeV. The data samples of e(+)e(-) collisions, collected by the BESIII detector at the BEPCII collider with a total integrated luminosity of 300 pb(-1), are analyzed. The total Born cross sections for the process e(+)e(-) -> K+ K- pi(0)pi(0) as well as the Born cross sections for the subprocesses e(+)e(-) -> phi pi(0)pi(0), K+(1460)K-, K-1(+)(1400)K-, K-1(+)(1270)K-, and K*(+) (892)K*(-) (892), are measured versus the center-of-mass energy. The corresponding results for e(+)e(-) -> K+ K- pi(0)pi(0) and phi pi(0)pi(0) are consistent with those of BABAR with better precision. By analyzing the cross sections for the tour subprocesses, K+(1460)K-, K-1(+)(1400)K-, K-1(+)(1270)K-, and K*(+) (892)K*(-) (892) a structure with mass M = (2126.5 +/- 16.8 +/- 12.4) MeV/c(2) and width Gamma = (106.9 +/- 32.1 +/- 28.1) NleV is observed with an overall statistical significance of 6.3 sigma, although with very limited significance in the subprocesses e(+)e(-) -> K-1(+)(1270)K-, and K*(+) (892)K*(-) (892). The resonant parameters of the observed structure suggest it can be identified with the phi(2170), thus the results provide valuable input to the internal nature of the phi(2170).

Using an e(+)e(-) annihilation data sample corresponding to an integrated luminosity of 2.93 fb(-1) collected at the center-of-mass energy of 3.773 GeV with the BESIII detector, we measure the absolute branching fractions of D+ -> eta eta pi(+), D+ -> eta pi(+pi 0), and D-0 ->eta pi(+) pi(-) to be (2.96 +/- 0.24 +/- 0.10+x10(-3), (2.23 +/- 0.15 +/- 0.10)x10(-3), and (1.20 +/- 0.07 +/- 0.04) x 10(-3), respectively, where the first uncertainties are statistical and the second ones are systematic. The D+ -> eta eta pi(+) decay is observed for the first time, and the branching fractions of D+(0) -> eta pi(+) pi(0(-)) are measured with much improved precision. In addition we test for CP asymmetries in the separated charge-conjugate branching fractions; no evidence of CP violation is found.

Using a data sample of (448.1 +/- 2.9) x 10( )(6)psi(3686) decays collected by the BESIII detector at the Beijing Electron Positron Collider (BEPCII), we observe the decays chi(cJ) -> phi phi eta (J = 0, 1, 2), where the chi(cJ) are produced via the radiative processes psi(3686) -> gamma chi(cJ) . The branching fractions are measured to be B(chi(c0) -> phi phi eta) = (8.41 +/- 0.74 +/- 0.62) x 10(-4), B(chi(c1) -> phi phi eta) = (2.96 +/- 0.43 +/- 0.22) x 10(-4), and B( chi(c2) -> phi phi eta) = (5.33 +/- 0.52 +/- 0.39) x 10(-4), where the first uncertainties are statistical, and the second are systematic. We also search for intermediate states in the phi phi or eta phi subsystems, but no significant structure is seen due to the limited statistics.

We report the first observation of the semimuonic decay D+ -> omega mu(+)upsilon(mu) using an e(+)e(-) collision data sample corresponding to an integrated luminosity of 2.93 fb(-1) collected with the BESIII detector at a center-of-mass energy of 3.773 GeV. The absolute branching fraction of the D+ -> omega mu(+)upsilon(mu) decay is measured to be BD+ -> omega mu(+)upsilon mu = (17.7 +/- 1.8(stat) +/- 1.1(syst)) x 10(-4). Its ratio with the world average value of the branching fraction of the D+ -> omega e(+)upsilon(mu) decay probes lepton flavor universality and it is determined to be BD+ -> omega mu(+)upsilon mu/BD+ -> omega mu(+)upsilon e(PDG) = 1.05 +/- 0.14, in agreement with the standard model expectation within one standard deviation.

Using a sample of (448.1 +/- 2.9) x 10(6) psi(3686) events collected with the BESIII detector, we perform the first partial wave analysis of psi(3686) -> K+K- eta. In addition to the well established states, phi(1020), phi(1680), and K-3(*)(1780), contributions from X(1750), rho(2150), rho(3)(2250), and K-2* (1980) are also observed. The X(1750) state is determined to be a 1(--) resonance. The simultaneous observation of the phi(1680) and X(1750) indicates that the X(1750), with previous observations in photoproduction, is distinct from the phi(1680). The masses, widths, branching fractions of psi(3686) -> K+K- eta, and the intermediate resonances are also measured.